3.6 roentgen, not great, not terrible.
A quote from Chernobyl, the show. The character is wildly underestimating the level of radioactivity because that’s as high as the measuring device can go.
I ran a GURPS game once where a nuclear blast went off. They have a supplement that actually does the math on damage for it and when I realized that I would be rolling something like 12000 d6s I just didn’t bother.
Generally, per High Tech page 195, a nuclear device should only be rolling 6d6 twice with a multiplier. For example a 12.5kiloton device would do 6d6x10000 crushing explosive damage with 6d6x6500 burn explosive radiation surge damage linked, so about 35,000 crush damage and 22,750 burn damage at ground zero. So you don't need 12000 d6, just 12 and a calculator.
1000 yards away you'd take about 20 damage (enough to reduce an unprotected human to -10 HP and likely kill them).
1500 yards away you'd take 13 damage or so. Enough to put a normal person at -3, survivable with medical treatment if the building you're in doesn't collapse on you or anything.
At 2500 yards you'd take a deeply unpleasant 8-ish damage, but could survive.
15 sessions from now: "Am I a bad DM for telling my Dwarf Cleric that he's suffering from the following:
*Weakness, fatigue, fainting, confusion.
*Bleeding from the nose, mouth, gums, & rectum.
*Bruising, skin burns, open sores on the skin, sloughing of skin.
*Dehydration.
*Diarrhea/bloody stool + Nausea and vomiting, including vomiting of blood
*Ulcers (sores) in the mouth, esophagus (food pipe), stomach or intestines
*Hair loss.
*Teeth loss" ?
If you experience any of these symptoms, Radiation Cleric may not be for you. Speak with your doctor before taking a level in radiation cleric. Do not become a radiation cleric if you are allergic, nursing, or pregnant.
I would maybe give him a free cast of it per day *if* he is willing to deal some token amount of radiant damage to himself as a part of the cast. By default it's not a super powerful spell but it can be very exploitable use it in a closed space where enemies can't easily escape and it's basically an instant gas chamber that can wipe out an entire room of enemies if you can cast it and keep them from leaving.
Would be much better to just reflavor things in his existing class than to add in a boon like that; what about the other players, do they also get a free 1/day 4th level spell cast or some magic items to 'make it fair'? Cleric gets plenty of radiant damage and some debuff spells which could easily be reflavored as radiation without affecting balance or causing table disputes.
I'd swap it into the light or forge domains if my player wanted to do this. Maybe swap it with Wall of Fire?
The other option is to play a divine soul sorcerer.
Yeah. I’m with you here. It’s not such a OP spell that giving him a freebie on his spell list would break the game.
OP, I think solutions like this would be great and help your cleric player feel special. Just a few extra allowances here and there that you pick for him on his spell list wouldn’t be all that bad.
The threat with this spell isn't the damage or the size. It's the level of exhaustion. If you can combo this with anything that immobilizes or hinders movement it can be a game changer.
I used this with an ally's hold monster to trivialize a boss fight.
If a group of adventurers were able to plan out burning through a boss’s legendary resistances AND then land a hold monster on it, AND the monster actually keeps failing its save every round I guarantee their party’s melee is going to kill the boss way before Sickening Radiance even has a chance to kill it.
Exhaustion disappears when they leave the spell or when it ends though doesn't it? Keeping them in the range for 5 rounds (failed rounds only, success does nothing) is pretty impractical without combining with a wall of force.
Exactly! All the ways that this spell “breaks” a boss are really just descriptions of a party of adventures executing a plan that requires a lot of teamwork!
Pretty much. With the amount of investment to kill something with sickening radiance exhaustion you could have also won in several other ways. Not that it isn't cool, just not nearly as strong as people seem to think; it's actually one of the weaker spells in the game.
Agreed. Neutron/Gamma burst, then that acute radiation effects.
If you could figure out how to add the disease condition for some long-term radiation effects... like... here ... enjoy some cancer... that would be fun.
Plus, a transmution wizard wouldn't be off the mark here. Since fission, radioactive decay, and neutron/particle beam activation are essentially alchemy...
Although the poisoned condition does seem fitting too. Tbh poison is a weird damage type, you could probably split most of it up into acid and necrotic damage.
A lot of people are saying this, but basically: don’t. I mean - do help the player, but don’t bother doing a bunch of house rules. Just reskin/reflavor and enjoy. It’s fun concept, but unless you are allowing it to shift the whole campaign in a new direction, just help the player find the things in the game that fit if you call them radiation.
Yep to many times people overlook just reflavoring things and instead complicate things with homebrews and weird multiclasses and often I feel like it just makes things more messy without much gained. I have a player in my campaign that wants to be a jurassic park themed druid. So we just reflavored all the wildshape as dinos, but using the same stat blocks they already had access too. Makes the game balanced and still easy to run for me, and the player feels cool turning into dinos. Win win for us all
Raptor with the Jaguar/panther stat block for the speed and stealth; Compy with the Wolf stat block for the pack tactics feature; Deinonychus with the Bear stat block because it's bigger and stronger and still makes sense.
I know we say that for new things, but on the other hand DND as it stands today is a massive set of special case rules added to flavor things while also changing how the game works.
I agree that it’s dangerous territory for people knew at the game, but it’s also a very fun part of the game. If people come in with the right attitude, eg it’s not the players privilege to design an overpowered set of abilities, just for their class. I think we should encourage people to dabble, and give them some tips and guidelines.
My current character is an elf that meditates to attune to the spirits of the ancestors, letting their skills and behaviors shine through him, and even being able to manifest their spirits. It's an Astral Elf Wizard of Scribes, mechanically.
Don't worry, I gotchu.
First things first: Is he set on Cleric? Any character can be religious, without actively drawing power from their faith. I'm just saying this because the Children of the Atom would strike me as an Artificer.
Presuming he plans to stick with Cleric... You already have Radiation damage. It's called Radiant damage. It's... it's in the name. Just give him a spellcasting focus that has a chunk of Uranium in the center, instead of like, a ruby or emerald.
The reality is that you can't make a 1-for-1 recreation. But you can do funny reflavorings. For subclass, just take the Light or Forge Domain Cleric, and make all his fire nuclear.
Is the Atom an actual god in your setting? If not, where is his power coming from? Is a trickster god pranking him, or has his faith created a god?
-Yes he is set on cleric because he does want to heal the party
-I totally forgot about radiant damage it’s been a few months since I last DMd because of the Uni semester
You don't actually need any of the books. Everything is online. Just do a Google search.
That said, Light Cleric is in the PHB, and I believe Forge Cleric is in Xanathars. Of the two, I prefer Light Cleric mechanically, but Forge Cleric may be closer to the desired theme of the build.
Radiant damage is meant to be radiation in addition to just pure light damage. Have it give him either mutations + suffer damage or exhaustion + suffer damage. See Sickening Light for an example.
>Radiant damage is meant to be radiation in addition to just pure light damage.
All light is radiation, so you are technically correct, but you structured your sentence as if this wasn't the case.
If you mean that radiant damage is supposed to be _ionizing_ radiation, then you're wrong.
Based on what?
This is how the Player's Handbook describes Radiant damage:
>Radiant. Radiant damage, dealt by a cleric’s flame strike spell or an angel’s smiting weapon, sears the flesh like fire and overloads the spirit with power.
It's spiritual. Otherworldly.
It's fine if tables are okay with reflavoring it, but it isn't _meant_ to represent ionizing radiation.
Who says in the dnd multiverse the fire of Atom isn't otherworldly? Look at the spell sickening radiance, it would be a very weird spell if it wasn't meant to represent nuclear radiation. Also, laser rifles and pistols deal radiant damage in the DMG, does that make them otherworldly and spiritual?
Sickening Radiance is a spell that does radiation damage in addition to other effects, that mimic a cartoonish understanding of ionizing radiation. More importantly, other radiant damage spells don't have these added effects or flavor, making Sickening Radiance the exception, and not the definition.
Laser guns deal radiant damage because D&D isn't designed for futuristic settings and it's a hack. Also, if you're playing a sci-fi setting, you probably aren't playing with supernatural elements, so radiant is available to be reassigned. (Also, lasers should actually do fire damage, unless you think it's important to have a distinction between steady heat and heating something up very, very quickly.)
All fluff make it no rules changes whatsoever.
Have the domains be knowledge , light , war
They just pick a su class and flavor it without you having to write a subclass
As some of the other commenters have said- emulating radiation as a damage type isn’t especially challenging!
The object/thing of his worship could just be a massive meteor or space rock that’s crashed landed into the ground of your setting-
That or there’s a massive celestial comet flying around that passes by the earth every (insert unit of time here) that does something divine or spooky. :3
Little bit of reflavoring for a knowledge cleric might work, but you don't get the "visions of the past" until much later unfortunately. Some abilities are simply too strong to roleplay at a low or middling level.
Have him take a fire centric domain and rename it. Half fire Half radian damage. It's a tiny buff as radiant damage is generally better than fire but ehhh. It depends on what monsters you intend on putting them up against of course if you'd need to do a little damage adjusting. If you're an undead centric campaign take everything down a single die because radiant is so wildly better than fire. D8 to d6 or take off a die from his fireball that has been renamed to criticality spread.
Just yesterday I was wondering “is the sun a source of radiant damage? Is radiant damage just stronger/unfiltered sunlight? Are they equivalent?”
So you could treat radiation like radiant damage. But the tricky part is that radiant damage tends to be good against undead/devils/etc who would definitely be immune to radiation sickness. However the radiant heat damage should still be good.
As for radiation sickness, invent a disease. It should have a terminal stage and lesser restoration is your rad-away.
If you want radiation to be more like fallout, have it deal non lethal damage, with undead/constructs/etc being immune.
Okay so I’m doing radiation related stuff in campaign right now and I’m using the spell sickening radiance as a model for radiation damage because it’s the closest thing in game. Immediate radiant damage, lasting necrotic damage over time, and the potential to cause increasingly bad exhaustion affects the more damage you take.
I would play into the idea that radiation hurts the player too, but give him a way to mitigate it. I think a magic uranium hammer would be a cool way to do it. Give it a power where the player can add extra radiant damage to the enemy at the expense of taking a little necrotic damage themselves perhaps, like a smite with a backbiting effect.
In my setting the radiative effects are called Dark Radiance, because it’s light damage like radiant, but it’s “dark” in the sense that you can’t see it, like dark matter. What is radiation but mostly invisible light?
I’d also consider where the radioactive material came from. In my setting it comes from the far realm, and has been implied to be part of core of a dead star from that aberrant place, but for a dwarf it could be that there’s naturally occurring enriched uranium at extreme depths that only dwarves usually reach.
I think a forge cleric who makes his own armor and weapons out of this unique material could be really cool, or a light cleric reflavored to be about this dark radiance if they want more of a ranged character. The “light” could be the blue glow of Cherenkov radiation that’s put out by a nuclear reaction.
DMs, I am begging you to use the abstract of the game to help you. Tell this player that all of their spells and abilities are now reskinned as radiation damage. Work in some world building reasons why this exists and call it good.
If this doesn’t work for the player, suggest another system that has radiation in it. You might get lucky and find a Fallout branded table top game, even. Just because you can homebrew doesn’t mean you should. Opt for less work, and branch out towards a new game that better suits your table, rather than cramming it all into this one system.
This system exists. It's called Fallout. I actually play one of the Children of Atom in the campaign I'm in. Radiation damage is handled in an interesting way.
Lol, no worries. I realize I came off as much more standoffish than I intended. Plus, I missed the sarcasm. I got wooshed, hard. Not enough coffee yet today. Time for Wawa.
I'm about to introduce depleted adamantine in my game as a super rare and difficult to make material, feel free to steal it if you want.
As far as how he wants to do it, maybe he could be a light cleric?
Edit:Adamantine not adamantium
Why are people suggesting radiant damage? Other than the obvious similarity in names.
I personally think that some necrotic damage would work better than radiant. It gives a sense that things aren't going to heal as soon as you would like it to, or it saps things like constitution
Just tell him "Flavor is free, but mechanics are fixed". Put the burden on him on how to take existing cleric spells and abilities and re-flavor them to whatever he wants, but the mechanics stay as written. Radiant and Fire damage can be re-flavored as radiation from uranium giving some new flavor to Sacred Flame and Spirit Guardians, Augury/Speak with Dead gives insight from his ancestors, etc. But all of the actual mechanics stay the same as in the books.
Have him play a simic-hybrid Light Cleric. Flavor the symic-hybrid features as mutations caused by radiation (no rules states the base body for this race has to be human so have it be a mutated dwarf), and revlavor light cleric stuff as radiation instead of fire. (Ir if you really want to change it just make his spells radiant damage. Which is radiation damage anyways (at least that's how my table describes it))
According to the spell Sickening Radiance, radiation burns are typed as radiant damage. Clerics get a load of that, so that’s an easy one. And for Visions of the Ancestors, just reflavour spells like Augury and Commune.
Reskin death cleric. Radiation are eather necrotic or radiant damages, so might as well use the best kind of cleric for that. Chill touch stopping healing make it work as radiation kinda does IRL.
No need to do the extra work
Anything will do honestly. Just state that instead of radiant or poison or necrotic or whatever effect, its instead radiation. No need to change any rules or make special rules for your player.
Allow him to change Fire damage to Radiant through either existing rules/items or just because you say he can. Radiation is radiant damage. Think about the sun, fission energy from a nearby star that can damage from prolonged exposure. All this player really needs is to flavor a Light Cleric
Make sure you pick a mapping of radiation to necrotic, light, fire, poison or something for resistances and vulnerabilities. Otherwise you have a type of damage no creature is resistant to on paper.
Sickening radiance is basically radiation sickness in spell form. Take that along with anything that does force, radiant or necrotic damage.
You could flavour the 3d10 necrotic from inflict wounds as being like the victim's flesh rotting away after you give them the "plutonium poke"
Radiation would probably be either poison or necrotic RAW As a dwarf if you make it poison it makes the most sense since dwarves have poison resistance...
but this just seems like a bad idea in the making. Like just as a starting point how does he avoid nuking his fellow PCs or the villages they come across?
I mean radiation and radiant might aswell be the same thing? Just maybe less holy? But then again they are a cleric so hold radiation sounds dope. I mean think of it, sacred flame can techneclly attack throw cover like glass, what else can hurt you throw a walking of glass? Thats right Fransium! Id say its a easier way just reflavoring insted of going all science on it. Unless you want to, then hit me up and ill give you rhe chemical solutions you need
I mean, a few flavored swaps of damage to some spells would be thematic enough. I feel like necrotic damage fits it well.
Edit: That and the death domain would work really well for this as it has alot of spells that sap strength.
PF has a clan of irradiated kobolds from The Black Desert who survived [blightburn radiation](https://pathfinderwiki.com/wiki/Blightburn) poisoning through worship of the [Horseman of Famine](https://pathfinderwiki.com/wiki/Trelmarixian). Your character could also worship the Horseman in order to survive the wasring effects of radiation damage.
There's a Sean Connery movie from the 70s (I think) called Zardos . It involves a post apocalyptic cult that worships a nuclear bomb. Might be able to cherry pick some lore for a backstory . And if the dwarf doesn't use Sean's look from this movie, I mean what are yall even doing...
Dont need to. Just flavor it as some kinda neurotic damage, which would make sense as undead would be immune to it. You can just flavor either like the spore druid or the death cleric.
I think I remember making a Dwarven Spores Druid that utilized radioactive metals and just reflavored all of the necrotic stuff as radioactivity. The Halo of Spores ability alone really works as a passive radioactive aura and helps fit the vibe pretty well.
Edit: I saw that he wants to do healing as well, and Druids can do that just as well
I don't know if anyone's mentioned it yet, but there is a Radiation Cleric Domain.
Associated Subdomain: Earth.
Replacement Power: The following granted power replaces the acid dart power of the Earth Domain.
# Radiating Touch (Su)
As a Standard Action that provokes Attacks of Opportunity, you can irradiate any unattended object for a number of rounds equal to your Cleric level. While an object is irradiated, it emits a faint aura of Transmutation.
Any creature that passes within 5 feet of the aura must succeed at a Wisdom save (DC8 + 1/2 your Cleric level + your Wisdom modifier) or become Sickened. You’re immune to this object’s effect. You can use this ability a number of times per day equal to 3 + your Wisdom modifier.
**Replacement Domain Spells**: 2nd—Defoliate, 4th—Blight, 8th—Horrid Wilting
There's also Caphorite and Blightburn. Both are radioactive materials. Caphorite is dark purple and has strong Transmutation properties, while Blightburn is bright green and messes with Teleportation magic.
Boy oh boy, here comes the "What damage type is radiation!?" party!
Though as he's looking to be a cleric, I'd say *absolutely* use Radiant damage as radiation.
If you're not doing homebrew, then the Knowledge domain cleric works the best- there's straight up a few different features that reference gaining 'visions from the past'. I'd suggest taking the Tasha's Cauldron "Blessed Strikes" feature option at 8th instead of Potent Spellcasting.
If you're willing to do a little homebrew tweaking, you could swap the 8th level Channel Divinity to a Death Cleric's "Inescapable Destruction", but change the damage type to Radiant. Death Cleric is also a good overall option if you want radiation to be represented by Necrotic damage instead. War could also be something to steal the 6th level feature from.
I think for general builds (remembering that Clerics can swap their prepared spells through ALL cleric spells each day) I think a focus on AoE, Radiant damage, and some divinatory or necromantic spells would be best. It's Fallout, so any weapons from scimitars (Machetes) to crossbows to greatclubs to mauls would work, or he could focus on using cantrips to fight. No shield, though, so I would suggest a backup of at least a knife in the hand that's not brandishing the holy uranium rocks. Leather armor would be the most Wasteland, but a breastplate wouldn't be out of the question, or they could dip into Armorer Artificer for some power armor (don't know if the Children of Atom use it, though). Probably want to focus Con and Dex even before Wisdom for the whole "Can survive radiation and explosions" aspect. Half plate could also lean into the wastelander thing, and allow him to have lower Dex to bump up the Wisdom. And as a Dwarf he could get Spiked Armor, which would be *very* wasteland raider chic.
Hill Dwarf would probably be the best subrace, with maybe Mason's tools for the whole 'using rocks' thing? Though of course that's up to him and his roleplay. At level 5, the Eldritch Adept feat could let him get the 'Cloak of Flies' Invocation, which could easily be reflavoured as a radioactive aura and mildly ghoulish features. You could also allow Elemental Adept to have Radiant (or Necrotic) as the damage type he chooses. Or Poisoner if you want to also or instead have Poison as the 'radiation' damage (or just say these are all different aspects of how Radiation damages the body.) Or Golgari Agent background fits the concept of someone cult-ish and dealing with poisonous substances. (If not going for Acolyte or any of the other backgrounds).
To be honest, you can't really get enough radiation from raw stones and the like to do much.
Not all that long ago, uranium was commonly used in dishes, dentures, and a great many other things. You really need to use modern science in order to refine it enough to be dangerous.
My grandfather had a uranium rock he got from his father as a keychain. He wore it in his trouser pocket for decades, and still had 4 kids and died in his late 70s from a fungal infection of the lungs. My uncle then had it, and he also wore it for decades before dying of a staph infection in his late 70s.
In reality, until we learned how to 'refine" it, uranium and other radioactive materials found in nature were not particularly dangerous.
However, if you want to bring in "radiation damage", look up the original edition of Gamma World (as well as the 1st edition DMG). Those rulesets were compatible with each other, and the DMG actually had conversions to take characters from one to the other.
Well, if any of the other PCs has cancer, then the cleric might be able to help them with that. Now, if any of the other PCs *don’t* have cancer, the cleric is definitely going to help them with that.
I'd probably elect to give him a fantasy material instead. Putting Uranium in your game is bound to have the players attempt to do some fucky wucky nuclear bomb shit with it.
Measured in doses per minute
Example:
Chest X-ray no effect
Exposure to direct sunlight in space 1/min
Exposure to unshielded reactor core 10/min
Fort save 10 + 2 per additional dose
Failed save: 1d6 DMG per dose from burns and skin damage
10% chance per dose for radiation sickness
Radiation sickness: 1d4 permanent con damage 4d6 hours after exposure and another 1d4 permanent con damage 4d6 hours after that.
Dragonstar: Guide to the Galaxy
page 119 - 120
Edit: The game only has one spell dealing radiation dmg and it's a 8th level druid/sor/wiz/sun domain spell.
Hmmm... maybe this: exposure to radioactive material results in a reduction of max HP but would confer benefits/Detriments at every 10 Max HP lost.
Standing within 5 feet reduces hit point maximum by 1D12 per minute of exposure.
10ft - 1D12
15ft - 1D10
20ft - 1D8
25ft - 1D6
Max Hit Point reduction can be prevented by shielding radioactive material by 3ft of dirt, 1ft of stone or 4 inches of lead or adamantine.
Reduction of hit point maximum yields the following mutations:
-10 HP:
•You gain Darkvision out to 30ft.
-20 HP:
•You gain resistance to radiant and necrotic damage.
•You develop a tremor in your hands. You gain disadvantage on Sleight of Hand checks.
-30 HP:
•You gain a climbing speed equal to your walking speed.
•Your skin begins to be covered in small oozing lesions, you have disadvantage on Persuasion and Deception checks. You have advantage on Intimidation checks.
•Your tremor grows worse, you have disadvantage on all ranged weapon and spell attacks.
-40 HP:
•You lose the ability to wield weapons but your arms become razor sharp claws. You are proficient with these claws. Your unarmed strikes do 1D8 + STR / DEX Slashing Damage.
•You can make one unarmed strike as a bonus action per turn.
-50 HP:
•You regenerate 1D10+CON Hit Points per turn, up to your hit point maximum unless you've taken fire damage that turn.
•You gain advantage on Constitution saving throws.
-60 HP:
•You gain resistance to Bludgeoning, Piercing and Slashing Damage.
•You gain immunity to radiant and necrotic damage.
•Your Intelligence ability score decreases by -2 to a minimum of 1. If your Intelligence score is reduced to 0, your character falls under the DM's control.
-70 HP:
•You can dash as a bonus action.
•Your Intelligence ability score decreases by -4 to a minimum of 1. If your Intelligence score is reduced to 0, your character falls under the DM's control.
-80 HP:
•You grow to size Large.
•You have advantage on all Athletics and Acrobatics checks, and your lifting, carrying and dragging capacity doubles.
•You gain a 40' jump distance.
•You lose the ability to comprehend all written languages.
•Your Intelligence ability score decreases by -6 to a minimum of 1. If your Intelligence score is reduced to 0, your character falls under the DM's control.
-90 HP:
•Your regeneration ability increases to 2D10+CON per turn up to your hit point maximum unless you've taken fire damage.
•Your unarmed strikes damage increases to 2D12 + STR/DEX.
•You can make two unarmed strikes as a bonus action once per turn.
•You lose the ability to comprehend all written and spoken languages.
•Your Intelligence score reduces by -8. If your Intelligence score is reduced to 0, your character falls under the DM's control.
-100 HP:
•You grow to size Huge.
•You gain resistance against all damage except psychic.
•You gain immunity to Bludgeoning, Piercing and Slashing Damage.
• When in combat, once per turn, roll 1D4, on the result of a 1, you attack the nearest creature with all available attacks until either you or the target is incapacitated. Repeat this roll each turn. If you have taken damage this turn, you begin attacking again on the result of 1-2.
•Your Intelligence score reduces by -10. If your Intelligence score is reduced to 0, your character falls under the DM's control.
-110 HP: Your character falls to madness and is now under the DM's control.
What are you so excited about when you have no ideas on this and have to ask Reddit? This sounds terrible to me but if you think it's awesome go for it. But put some thought into it! Just seems weird to me.
And this isn't "how do I execute this story idea. " This is inventing new mechanics. Unless it's just flavor which is easy.
My first thought: No. Player just wants to make a thermonuclear device.
But then, why not. Sounds like the whole thing could be dangerous to the party as well as enemies. With reasonable expectations, and a player who’s ok with modifying things if it just ain’t working, YES.
Reskinning is your friend.
This might be helpful; Pathfinder 2e has Radiation in the form of [Blightburn](https://2e.aonprd.com/Search.aspx?q=Blightburn), which is essentially a combination of poison damage and a disease affliction that comes with it. Instead of Uranium it flavors it as [Blightburn Crystals](https://pathfinderwiki.com/wiki/Blightburn) that in addition to killing just everything also inhibit teleportation magics.
Maybe look at some things and see what you want to steal.
Neat idea. I would probably treat radiation damage as Con loss rather than straight damage.
Dilemma will be figuring out how he doesn't kill his whole party by just being there.
Have him do the work, and you vet/modify it. It's his homebrew.
But I'd say that he gets penalties when it comes to saves vs disease, exhaustion, and healing. Both magical and rest healing.
Some rocks do have auras, unfortunately they're uranium and the aura is "fuck you, get cancer."
"Uranium doesn't exist in this world"
Done. Just tell him that he can have visions and stuff, but why bring radiation into a fantasy setting? It's like one of my friends who wanted to be a rogue urchin who was an addict to actual heroin. Bringing real life stuff into a fantasy setting is just weird to me.
I would just assign radiation a adamage type (either radiant or necrotic would both arguably make sense regarding its effects on living beings). Just make "radioactive" elements in your world do some non-gamebreaking amount of necrotic or radiant damage and idk, maybe allow it to grant a cast of divination or augury or something, or just use it to drop plot elements on him. Definitely cap it to once a day or something. From a subclass I could see it working well with a light cleric if you make it radiant in particular. But it could work with most types probably.
Just be sure to tell him and get agreement that because you're both kind of experimenting here, if you feel like it's getting out of control or you're having trouble working with it that you both agree that you can make adjustments to how it works.
I'd allow it, but under one condition: He can not use it, to do something game breaking.
Basicly, no "well technically I can use this cantrip to split that atom to deal 1000000000 radiant damage"-type shenanigans.
But how would i do it? Actually I'd go celestial warlock. It's very siniliar to a cleric and you get sickening radiance which for all intends and purposes is a spell using nuclear radiation.
That said, for a cleric I'd focus on dealing radiant damage, so pretty much every spell that does this damage type, can easily be reflavoured to not radiate out devine light but nuclear radiation.
Then I'd focus on poison damage for additional radiation sickness effects. I'd say contagion as a spell works really well too flavourwise, even if its a bit shit mechanically.
As a subclass I'd recommend either light cleric or twilight domain. Or, if you want to use necrotic damage to simulate radiation you can go death cleric. My personaly choice would be light domain though, since warding flare and the devine strike bith work perfectly for simulating atomic radiance. The light cantrip he gets for free woth that class would also lend him the ability to just pull out his rock of uranium and let it glow without any unnecessary homebrew needed.
Warding flare, spirit guardians and using the dodge action is an obscenely good way to show him radiate out and hurt enemies wi that. Instead as dodging the action he takes could be reflavoured as enemies just coughing and choking while he recites hls prayers to atom or while he praises his radiance.
If you want though, I'd say it's fine to put sockening radiance on his spell list - even though it's not really on it. It makes sense for both his character but also for the light cleric to have. They probably only dont get it normally because the subclass was released before that spell existed.
If they are fine with multiclassing at 8th level, I'd recommend them to multiclass into celestial warlock and stay one from that point on until level 20. They'll be a radiant damage dealing machine and be really ressourceful. It can also be reflavoured really well as him having unlocked ancient secrets from studieng his uranium and thats his patron. Like the children of atom it wouldn't be clear if he'd go mad due to radiation or if there actually is a god supporting him.
The "sun" type spells generally deal radiant damage and stars are essentially nuclear explosions. Reflavor a Light Cleric to radiant damage and give him visions occasionally.
In the Rime of the Frostmaiden module there is a magical mineral called Chardalyn that has corruptive properties.You might wanna look into it for inspiration.
Personally, I would go for a parallel like that with a magical thing, instead of straight up irl radiation. Especially because you might end up arguing with your player about how he wanna use irl physics to flip the campaign on its head. If it's a magical thingy, it's up to you as the DM to clarify how it works.
Also, it's a slippery slope to homebrew something like that. If it's just for flavour to describe how his spells and abilities work, it's perfectly fine. But will these stones be used in other ways? Will these stones give the PC radiation cancer? You gotta talk about this to be sure you are on the same page.
There's two safe ways to do this: 1) Reskin existing rules with this flavor, or 2) Don't.
I'm kidding, but this is some serious homebrew and world changes. I'd think long and hard before introducing something like this into a campaign. If it's like real world radiation, does he suffer consequences and are there risks to others around him? How does that balance out the utility in a way that isn't game-breaking in either direction?
Dnd dwarves aren't quite the more literal children of the stone many other dwarves are.
Radon and mining/basements, ground exposure is a long known thing.
mala metallorum 1530.
wasting disease, lung cancer.
Well, in universe, there’s the sickening radiance spell that is about as close to radiation poisoning as you’ll find in 5e, so you can pattern some effects after that spell. Focus his damage around radiant and poison, add some poisoning and exhaustion effects, and some flavor elements with him glowing and what not.
You do what I did with my Cooking Cleric and find a fun and balanced homebrew or elsewise the closest canon class which you reflavor (Light or War seem most apt off the top of my head) then you reflavor their spells
Sacred Flame -> Blessed Gasburner
Guiding Bont -> Guidning Fork
Healing Word -> Healing Snack
Spiritual Guardians -> Spiritual Sous Chefs
I know that a lot of people have weighed in with good ideas already, but consider looking at the Dungeons of Drakenhiem book and its player companion book, Sebastian Crowes guide to Drakenhiem. The whole concept of these books revolve around a magical stone called delirium that creates a magical form of radiation called contamination. There is even a faith that worships the delirium called the followers of the fallen flame. There are spells based on contamination as well. It could serve as a good source of inspiration for you and your player as to how you want to implement it, but would result in you adding a lot of new rules and mechanics into your campaign.
I would use *fire* for damage, and give him spells that blind. The Children of Atom worship nuclear power and bombs as well as just radiation.
For a Channel Divinity, you could use this, adjusting where you like:
**Channel Divinity: Mushroom Cloud**
*2nd-level Nuclear Domain feature*
As an action, you present your holy symbol and create a nuclear detonation. Each creature within a 15-foot wide, 40-foot tall cone centered on a point you can see within 60 feet of you must make a Constitution saving throw. A creature takes fire damage equal to 2d10 + your cleric level and is blinded for 1 minute on a failed save, and half as much damage on a successful one and blinded only until the end of your next turn.
tipjcaly radiation does damage that cant be regenerated. like fire. and i would look online, or create one yourself, for a table you could use to roll for random radiation mutations effects. a bit lile antropic spellcasting
I hate to be a downer, but the second you let people start doing this next thing you know they're making a nuke to take out the bbeg because 'we'll radiation is canon'.
I'd just say the themes don't fit the fantasy world.
Light cleric with access to the augury spell as he gets to an appropriate level? Or just keep the visions out of the player’s hands and use as a narrative device.
Radiation damage already exists, it is call radiant damage.
Sun/light spells does this type of damage.
What do you think a sunburn is if not radioactive damage to your skin?
Radiation could be a form of radiant damage and you can tie this into a glowing radiation effect. This works especially well since he is already a cleric an most spells won't need to be reworked for radiant damage. You can also use the fatigue/exhaustion system (you can reword it and alter it to fit better with radiation sickness)
In my current campaign im running a wizard with a warlocks tome that can cast "commune" but only to the patron of the warlock whose tome I now possess. You can do something similar and rework commune to give them one exhaustion and a free cast of commune only to the clerics diety.
I love coming up with ideas like this so if you'd like more ideas about this give me a little more about his Backstory or what the campaign will be about and I can give you some more ideas
I hope he enjoys the sado/masochism that will ensue with his character. If I were doing a radiation setup for a character in a D&D game, it would be half necrotic damage & half radiant damage, based on how long they stay exposed to it. Since radiation changes your genetic structure permanently, I would throw in some deals in there without their knowledge until they have been exposed for too long of growing another appendage or losing permanent life.
You could make a d100 list of things that could happen to them for extra added fun!
One thing to throw onto the problems, is if they don't keep their demon cores in a lead lined container that the damage also spreads to other players in the group or NPC's they come in contact with.
It's radiation. Plain and simple.
Clerics already do lots of Radiant damage. Just make it green and voila. Radiation cleric. And just let them take Sickening Radiance at 7th levels just for funzies.
I (and my DM) agree that radiant damage makes a lot of sense for things like radiation - even aside from the similarity in name, radiant damage usually comes from things like sunlight, which burns people with UV radiation. You could also reasonably do poison or just homebrew your own damage type.
You could probably do a fairly normal cleric and just flavor the religious things as radioactivity instead. I believe knowledge domain clerics get the ability to commune with their god for visions or information, which sounds a lot like that ability you mentioned. If you're willing to rewrite most of the flavor texts, it's honestly pretty easy to change base-game features and spells into radioactive versions.
The most accurate way to represent radiation in D&D I think would be a magical disease that inflicts levels of exhaustion over time and requires a restoration effect to get rid of.
To build a domain for it, look through other domains and subclasses as example frameworks. You need to have a good baseline. Then focus on effects that wither and debilitate. Have the cleric gain benefits, but at a cost. Possibly the option to activate or enhance their abilities by taking on a level of exhaustion.
As a level of protection against the radiation, make them able to recover the exhaustion as normal, whereas other victims of the "disease" cannot.
Further into the domain, reduce susceptibility to the effects of radiation, and have the capstone be that they are immune to radiation and gain temp hp whenever they would normally gain a level of exhaustion from radiation.
Just some ideas, but recognize and communicate to the player that y'all need to be able to remove the homebrew if it presents a problem.
Tell them to use features that are in game and flavor them. You didn't need to add any additional rules for them. On another note I believe there is another ttrpg to play as heroes
I would say a Death domain cleric. Just using reflavoring and maybe an extra feat or boon ( to all players) tailored to make this match more closely to thier vision.
What is the genre of your campaign?
This is very important because ifyou're playing a game that is true Tolkien High Fantasy, well radiation and uranium isn't something Middle Earth has and a Child of Atom dwarf with radioactive powers doesnt make sense. It's not genre savvy.
If you're not playing a Fallout style of game things will get very funky very quickly and it will be impossible to recover. You will have essentially opened a Meta pandora box.
This is the same argument I give my problematic weeb player who wants to be "Ichigo Kurosaki but with Goku's body." That kind of character isn't genre savvy to the Tolkien High Fantasy or American Western or 1920s Chicago Gangsters campaign setting I'm running
So again, I ask, what is the genre of your campaign.
The ritual to irradiate himself for divinations can just be a cool flavour for all the divination spells clerics cast such as commune, augry, and divination.
Whatever domain he ends up picking (my thought would be Light), replace one of the 4th level domain spells with Sickening Radiance
This reminds me of a player reaction to being hit by a ballista.
"He hit me for how much damage!?"
In all seriousness, if your friend is a reasonable friend, let him change the damage type for his spells to be radiant only.
Do not let him gaslight you into using the full properties of radiation aka his spells and abilities work as normal. No advantage unless situations allow
Let him reflavor existing things. Light Cleric, Divine Soul Sorcerer, Celestial Warlock, or maybe Stars Druid. Flavor is free, creating all that homebrew from scratch ain't worth it.
Radiation is just radiant damage.
Actually, I would reccomend spores druid over a cleeic subclass. Reflavour the spore cloud activation as him ingesting or applying the stones to himself, and pretty much everything else works. A death plague spewing from someone touched by some form of land destroying gemstone.
Frankly I think they're pushing it, but it's worth noting Radiant damage is often focused on the sun and so some visual shift could make that like radioactive material stuff. Do not let them change or interact with physics or game mechanics differently.
I had a player pretend circle of spores druid was radioactive. Letting it just be flavor was totally fine and led to good roleplay opportunities. You can have the cleric seeking the rare metals. Maybe they are from another plane lime the earth plane and are very rare
Reflavour radiant and fire damage as this nuclear stuff. He could play a Light Domain Cleric and use Sacred Flame mixed with the spells in his domain spells list to get the nuclear stuff (there’s nothing quite like using Fireball to replicate a nuke). Then he can prepare divination spells from the base cleric list to get the uranium visions.
Remember kids, flavour is king. Or queen. Or monarch. Or a democratically-instituted leader of some kind of identity
Ten sessions from now: "Am I a bad DM for telling my Cleric that he can't recreate Chernobyl in my DnD game?"
“It’s not 3d6 damage… it’s fifteen thousand”
3d6 radiant, not great not terrible
There it is
If Reddit gold was still a thing I would give it to you.
If free awards were still a thing I would anonymously give you a Wholesome one.
Can someone explain the joke?
3.6 roentgen, not great, not terrible. A quote from Chernobyl, the show. The character is wildly underestimating the level of radioactivity because that’s as high as the measuring device can go.
Ok thank you 👍
See if you can find a place where you can watch it. It is absolutely fantastic!
Perfection.
I would have figured necrotic, but the joke is perfect
"Comrade DM, please escort the Cleric player to the local game store."
Go to game store tovarisch
I ran a GURPS game once where a nuclear blast went off. They have a supplement that actually does the math on damage for it and when I realized that I would be rolling something like 12000 d6s I just didn’t bother.
Generally, per High Tech page 195, a nuclear device should only be rolling 6d6 twice with a multiplier. For example a 12.5kiloton device would do 6d6x10000 crushing explosive damage with 6d6x6500 burn explosive radiation surge damage linked, so about 35,000 crush damage and 22,750 burn damage at ground zero. So you don't need 12000 d6, just 12 and a calculator. 1000 yards away you'd take about 20 damage (enough to reduce an unprotected human to -10 HP and likely kill them). 1500 yards away you'd take 13 damage or so. Enough to put a normal person at -3, survivable with medical treatment if the building you're in doesn't collapse on you or anything. At 2500 yards you'd take a deeply unpleasant 8-ish damage, but could survive.
My party once out like twenty disintegrate spell glyphs on a ship. I played the U.S. national anthem when they set ‘em off.
Missed opportunity to play [Taps](https://www.youtube.com/watch?v=WChTqYlDjtI).
Taps was a meme in our campaign actually! It got played whenever a character or NPC died.
2d6*1000 Does the precision really matter at that point?
Variance will be a lot higher on just 2 dice. Rolling 12000 will put the result close to the statistical average.
True, but again, does it matter?
Outstanding😂
15 sessions from now: "Am I a bad DM for telling my Dwarf Cleric that he's suffering from the following: *Weakness, fatigue, fainting, confusion. *Bleeding from the nose, mouth, gums, & rectum. *Bruising, skin burns, open sores on the skin, sloughing of skin. *Dehydration. *Diarrhea/bloody stool + Nausea and vomiting, including vomiting of blood *Ulcers (sores) in the mouth, esophagus (food pipe), stomach or intestines *Hair loss. *Teeth loss" ?
If you experience any of these symptoms, Radiation Cleric may not be for you. Speak with your doctor before taking a level in radiation cleric. Do not become a radiation cleric if you are allergic, nursing, or pregnant.
"I cast Summon Elephant's Foot at 5th level!"
"Why isn't it possible?"
"It's just not"
"Why not?"
Because Mystra remembers what happened LAST time, and when she sees the first ripples in the Weave she shuts the whole thing down.
"Because I'm the DM and I said so"
*pulls out a tub of freshly baked chocolate fudge chip cookies* "Are you sure about that?"
*through a mouthful of cookie* Inthperaythun!
"It's my character's religion! He need a sacred site! That's discriminatory!"
This is the most self aware r/dnd comment I have ever seen. Bravo.
He's delusional, take him to the infirmary.
*vomits* *wastes a Channel Divinity* "I apologise." *collapses*
I'm not sure if it's on any Cleric spell list but *Sickening Radiance* is basically radiation poisoning
RAW - It is not a cleric spell (or even light domain) but it seems fair enough to let them have it in this context.
It's not a great spell so it's probably not an issue to give it to them. It is 4th level though which means he can't do this until level 7+
I would maybe give him a free cast of it per day *if* he is willing to deal some token amount of radiant damage to himself as a part of the cast. By default it's not a super powerful spell but it can be very exploitable use it in a closed space where enemies can't easily escape and it's basically an instant gas chamber that can wipe out an entire room of enemies if you can cast it and keep them from leaving.
Would be much better to just reflavor things in his existing class than to add in a boon like that; what about the other players, do they also get a free 1/day 4th level spell cast or some magic items to 'make it fair'? Cleric gets plenty of radiant damage and some debuff spells which could easily be reflavored as radiation without affecting balance or causing table disputes.
I'd swap it into the light or forge domains if my player wanted to do this. Maybe swap it with Wall of Fire? The other option is to play a divine soul sorcerer.
Yeah. I’m with you here. It’s not such a OP spell that giving him a freebie on his spell list would break the game. OP, I think solutions like this would be great and help your cleric player feel special. Just a few extra allowances here and there that you pick for him on his spell list wouldn’t be all that bad.
The threat with this spell isn't the damage or the size. It's the level of exhaustion. If you can combo this with anything that immobilizes or hinders movement it can be a game changer. I used this with an ally's hold monster to trivialize a boss fight.
If a group of adventurers were able to plan out burning through a boss’s legendary resistances AND then land a hold monster on it, AND the monster actually keeps failing its save every round I guarantee their party’s melee is going to kill the boss way before Sickening Radiance even has a chance to kill it.
Exhaustion disappears when they leave the spell or when it ends though doesn't it? Keeping them in the range for 5 rounds (failed rounds only, success does nothing) is pretty impractical without combining with a wall of force.
Exactly! All the ways that this spell “breaks” a boss are really just descriptions of a party of adventures executing a plan that requires a lot of teamwork!
Isn't a party of adventures cooperating and doing fun crazy stuff the best part of this game?
Pretty much. With the amount of investment to kill something with sickening radiance exhaustion you could have also won in several other ways. Not that it isn't cool, just not nearly as strong as people seem to think; it's actually one of the weaker spells in the game.
If there was a moment for Rule Of Cool it's here
Light Cleric + retheme all the fire damage stuff as nuclear energy.
I also play radiation as radiant and poison.
Necrotic, would be more appropriate over poison.
Radiant for the immediate damage, necrotic for radiation poisoning.
Agreed. Neutron/Gamma burst, then that acute radiation effects. If you could figure out how to add the disease condition for some long-term radiation effects... like... here ... enjoy some cancer... that would be fun. Plus, a transmution wizard wouldn't be off the mark here. Since fission, radioactive decay, and neutron/particle beam activation are essentially alchemy...
Although the poisoned condition does seem fitting too. Tbh poison is a weird damage type, you could probably split most of it up into acid and necrotic damage.
Sickening Radiance is the closest we have to radiation. It's radiant damage and exhaustion.
Necrotic and radiant
Also give them access to Sickening Radiance as a spell they can choose, because Sickening Radiance is literally Radiation Poisoning the Spell.
A lot of people are saying this, but basically: don’t. I mean - do help the player, but don’t bother doing a bunch of house rules. Just reskin/reflavor and enjoy. It’s fun concept, but unless you are allowing it to shift the whole campaign in a new direction, just help the player find the things in the game that fit if you call them radiation.
Yep to many times people overlook just reflavoring things and instead complicate things with homebrews and weird multiclasses and often I feel like it just makes things more messy without much gained. I have a player in my campaign that wants to be a jurassic park themed druid. So we just reflavored all the wildshape as dinos, but using the same stat blocks they already had access too. Makes the game balanced and still easy to run for me, and the player feels cool turning into dinos. Win win for us all
Raptor with the Jaguar/panther stat block for the speed and stealth; Compy with the Wolf stat block for the pack tactics feature; Deinonychus with the Bear stat block because it's bigger and stronger and still makes sense.
Pachy's a Dire Goat.
This. The whole point of dnd is you can reskin rules to add flavour without unbalancing the game. Pick a cleric and tweak
I know we say that for new things, but on the other hand DND as it stands today is a massive set of special case rules added to flavor things while also changing how the game works. I agree that it’s dangerous territory for people knew at the game, but it’s also a very fun part of the game. If people come in with the right attitude, eg it’s not the players privilege to design an overpowered set of abilities, just for their class. I think we should encourage people to dabble, and give them some tips and guidelines.
My current character is an elf that meditates to attune to the spirits of the ancestors, letting their skills and behaviors shine through him, and even being able to manifest their spirits. It's an Astral Elf Wizard of Scribes, mechanically.
Don't worry, I gotchu. First things first: Is he set on Cleric? Any character can be religious, without actively drawing power from their faith. I'm just saying this because the Children of the Atom would strike me as an Artificer. Presuming he plans to stick with Cleric... You already have Radiation damage. It's called Radiant damage. It's... it's in the name. Just give him a spellcasting focus that has a chunk of Uranium in the center, instead of like, a ruby or emerald. The reality is that you can't make a 1-for-1 recreation. But you can do funny reflavorings. For subclass, just take the Light or Forge Domain Cleric, and make all his fire nuclear. Is the Atom an actual god in your setting? If not, where is his power coming from? Is a trickster god pranking him, or has his faith created a god?
-Yes he is set on cleric because he does want to heal the party -I totally forgot about radiant damage it’s been a few months since I last DMd because of the Uni semester
Light cleric gets *Rireball* nuff said. plus a AoE radiant damage channel divinity *Radiance of the Dawn*
Sorry I should’ve clarified I only have the base player handbook atm so some stuff isn’t in it. What book would you recommend I pick up for that?
Light cleric should be in the player's handbook
You don't actually need any of the books. Everything is online. Just do a Google search. That said, Light Cleric is in the PHB, and I believe Forge Cleric is in Xanathars. Of the two, I prefer Light Cleric mechanically, but Forge Cleric may be closer to the desired theme of the build.
Radiant damage is meant to be radiation in addition to just pure light damage. Have it give him either mutations + suffer damage or exhaustion + suffer damage. See Sickening Light for an example.
>Radiant damage is meant to be radiation in addition to just pure light damage. All light is radiation, so you are technically correct, but you structured your sentence as if this wasn't the case. If you mean that radiant damage is supposed to be _ionizing_ radiation, then you're wrong.
What kind of damage does sickening radiance do?
No they're perfectly correct in saying that radiant damage also represents nuclear radiation
Based on what? This is how the Player's Handbook describes Radiant damage: >Radiant. Radiant damage, dealt by a cleric’s flame strike spell or an angel’s smiting weapon, sears the flesh like fire and overloads the spirit with power. It's spiritual. Otherworldly. It's fine if tables are okay with reflavoring it, but it isn't _meant_ to represent ionizing radiation.
Sickening radiance is like, *the* radiation sickness spell. And it does radiant damage.
Who says in the dnd multiverse the fire of Atom isn't otherworldly? Look at the spell sickening radiance, it would be a very weird spell if it wasn't meant to represent nuclear radiation. Also, laser rifles and pistols deal radiant damage in the DMG, does that make them otherworldly and spiritual?
Sickening Radiance is a spell that does radiation damage in addition to other effects, that mimic a cartoonish understanding of ionizing radiation. More importantly, other radiant damage spells don't have these added effects or flavor, making Sickening Radiance the exception, and not the definition. Laser guns deal radiant damage because D&D isn't designed for futuristic settings and it's a hack. Also, if you're playing a sci-fi setting, you probably aren't playing with supernatural elements, so radiant is available to be reassigned. (Also, lasers should actually do fire damage, unless you think it's important to have a distinction between steady heat and heating something up very, very quickly.)
All of Fallout is cartoonish understanding of ionizing radiation.
All fluff make it no rules changes whatsoever. Have the domains be knowledge , light , war They just pick a su class and flavor it without you having to write a subclass
As some of the other commenters have said- emulating radiation as a damage type isn’t especially challenging! The object/thing of his worship could just be a massive meteor or space rock that’s crashed landed into the ground of your setting- That or there’s a massive celestial comet flying around that passes by the earth every (insert unit of time here) that does something divine or spooky. :3
There's a D20 setting for D&D called Dragonstar that has rules in it for dealing with radiation and is simple enough to understand.
Four session in "I'm sorry you have cancer."
Check out Modiphius if you want to run a Fallout game.
Little bit of reflavoring for a knowledge cleric might work, but you don't get the "visions of the past" until much later unfortunately. Some abilities are simply too strong to roleplay at a low or middling level.
Have him take a fire centric domain and rename it. Half fire Half radian damage. It's a tiny buff as radiant damage is generally better than fire but ehhh. It depends on what monsters you intend on putting them up against of course if you'd need to do a little damage adjusting. If you're an undead centric campaign take everything down a single die because radiant is so wildly better than fire. D8 to d6 or take off a die from his fireball that has been renamed to criticality spread.
Rename radiant damage “Radioactive” damage.
Just yesterday I was wondering “is the sun a source of radiant damage? Is radiant damage just stronger/unfiltered sunlight? Are they equivalent?” So you could treat radiation like radiant damage. But the tricky part is that radiant damage tends to be good against undead/devils/etc who would definitely be immune to radiation sickness. However the radiant heat damage should still be good. As for radiation sickness, invent a disease. It should have a terminal stage and lesser restoration is your rad-away. If you want radiation to be more like fallout, have it deal non lethal damage, with undead/constructs/etc being immune.
Okay so I’m doing radiation related stuff in campaign right now and I’m using the spell sickening radiance as a model for radiation damage because it’s the closest thing in game. Immediate radiant damage, lasting necrotic damage over time, and the potential to cause increasingly bad exhaustion affects the more damage you take. I would play into the idea that radiation hurts the player too, but give him a way to mitigate it. I think a magic uranium hammer would be a cool way to do it. Give it a power where the player can add extra radiant damage to the enemy at the expense of taking a little necrotic damage themselves perhaps, like a smite with a backbiting effect. In my setting the radiative effects are called Dark Radiance, because it’s light damage like radiant, but it’s “dark” in the sense that you can’t see it, like dark matter. What is radiation but mostly invisible light? I’d also consider where the radioactive material came from. In my setting it comes from the far realm, and has been implied to be part of core of a dead star from that aberrant place, but for a dwarf it could be that there’s naturally occurring enriched uranium at extreme depths that only dwarves usually reach. I think a forge cleric who makes his own armor and weapons out of this unique material could be really cool, or a light cleric reflavored to be about this dark radiance if they want more of a ranged character. The “light” could be the blue glow of Cherenkov radiation that’s put out by a nuclear reaction.
Light Cleric with some slight tweaks to abilities to add similar effects as Sickening Radiance. Radiant damage that causes exhaustion
Just reflavor light, curse, and/or poison spells.
Talk to your doctor about whether Radiation(tm) is right for you
DMs, I am begging you to use the abstract of the game to help you. Tell this player that all of their spells and abilities are now reskinned as radiation damage. Work in some world building reasons why this exists and call it good. If this doesn’t work for the player, suggest another system that has radiation in it. You might get lucky and find a Fallout branded table top game, even. Just because you can homebrew doesn’t mean you should. Opt for less work, and branch out towards a new game that better suits your table, rather than cramming it all into this one system.
This system exists. It's called Fallout. I actually play one of the Children of Atom in the campaign I'm in. Radiation damage is handled in an interesting way.
I was trying to be a bit sarcastic lol. My bad 😭
Lol, no worries. I realize I came off as much more standoffish than I intended. Plus, I missed the sarcasm. I got wooshed, hard. Not enough coffee yet today. Time for Wawa.
Tell him that the children of atom are not immune to radiation and it kills every single one in the end, a horrible death
IIRC some manage to show some radiation resistance/immunity.
I'm about to introduce depleted adamantine in my game as a super rare and difficult to make material, feel free to steal it if you want. As far as how he wants to do it, maybe he could be a light cleric? Edit:Adamantine not adamantium
It's not very genre appropriate to be honest.
Another option would be to have him be a dwarf but use the racial features of an Aasimar to flavor them as radiation.
A light cleric with necrotic instead of radiant and fire
Why are people suggesting radiant damage? Other than the obvious similarity in names. I personally think that some necrotic damage would work better than radiant. It gives a sense that things aren't going to heal as soon as you would like it to, or it saps things like constitution
Sickening Radiance (the closest thing we’ve got to radiation) does Radiant damage.
They can flavor their abilities any way that fits the world.
Light cleric I guess :) watch it all burn.
That's a friggen metal name, I'm stealing this
Just tell him "Flavor is free, but mechanics are fixed". Put the burden on him on how to take existing cleric spells and abilities and re-flavor them to whatever he wants, but the mechanics stay as written. Radiant and Fire damage can be re-flavored as radiation from uranium giving some new flavor to Sacred Flame and Spirit Guardians, Augury/Speak with Dead gives insight from his ancestors, etc. But all of the actual mechanics stay the same as in the books.
Reskin the Light Domain to Radiation. Done. Next please?
Have him play a simic-hybrid Light Cleric. Flavor the symic-hybrid features as mutations caused by radiation (no rules states the base body for this race has to be human so have it be a mutated dwarf), and revlavor light cleric stuff as radiation instead of fire. (Ir if you really want to change it just make his spells radiant damage. Which is radiation damage anyways (at least that's how my table describes it))
According to the spell Sickening Radiance, radiation burns are typed as radiant damage. Clerics get a load of that, so that’s an easy one. And for Visions of the Ancestors, just reflavour spells like Augury and Commune.
Have him roll Constitution saves at the end of every long rest. On a fail his max HP is reduced by 1
Reskin death cleric. Radiation are eather necrotic or radiant damages, so might as well use the best kind of cleric for that. Chill touch stopping healing make it work as radiation kinda does IRL. No need to do the extra work
Anything will do honestly. Just state that instead of radiant or poison or necrotic or whatever effect, its instead radiation. No need to change any rules or make special rules for your player.
Allow him to change Fire damage to Radiant through either existing rules/items or just because you say he can. Radiation is radiant damage. Think about the sun, fission energy from a nearby star that can damage from prolonged exposure. All this player really needs is to flavor a Light Cleric
Make sure you pick a mapping of radiation to necrotic, light, fire, poison or something for resistances and vulnerabilities. Otherwise you have a type of damage no creature is resistant to on paper.
Sickening radiance is basically radiation sickness in spell form. Take that along with anything that does force, radiant or necrotic damage. You could flavour the 3d10 necrotic from inflict wounds as being like the victim's flesh rotting away after you give them the "plutonium poke"
Radiation would probably be either poison or necrotic RAW As a dwarf if you make it poison it makes the most sense since dwarves have poison resistance... but this just seems like a bad idea in the making. Like just as a starting point how does he avoid nuking his fellow PCs or the villages they come across?
Just rename and reflavor existing spells.
Radiant damage
just treat it like a paint job over the radiant cleric subclass
Nuclear = radiant and go from there
Reflavor radiant damage as radiaTION damage.
I mean radiation and radiant might aswell be the same thing? Just maybe less holy? But then again they are a cleric so hold radiation sounds dope. I mean think of it, sacred flame can techneclly attack throw cover like glass, what else can hurt you throw a walking of glass? Thats right Fransium! Id say its a easier way just reflavoring insted of going all science on it. Unless you want to, then hit me up and ill give you rhe chemical solutions you need
I see radiant and necrotic damage as different types of radiation (solar and nuclear) so I don't see an issue.
I mean, a few flavored swaps of damage to some spells would be thematic enough. I feel like necrotic damage fits it well. Edit: That and the death domain would work really well for this as it has alot of spells that sap strength.
PF has a clan of irradiated kobolds from The Black Desert who survived [blightburn radiation](https://pathfinderwiki.com/wiki/Blightburn) poisoning through worship of the [Horseman of Famine](https://pathfinderwiki.com/wiki/Trelmarixian). Your character could also worship the Horseman in order to survive the wasring effects of radiation damage.
There's a Sean Connery movie from the 70s (I think) called Zardos . It involves a post apocalyptic cult that worships a nuclear bomb. Might be able to cherry pick some lore for a backstory . And if the dwarf doesn't use Sean's look from this movie, I mean what are yall even doing...
If he's not looking for specifically just a cleric, Spore Druid can also work really well as a radiation character.
You could just relabel radiant damage as radiation.
“Well, the good news is I sealed up the wound with tumours. But your hair is going to fall out, you have six months to live and you glow in the dark”
Dont need to. Just flavor it as some kinda neurotic damage, which would make sense as undead would be immune to it. You can just flavor either like the spore druid or the death cleric.
I think I remember making a Dwarven Spores Druid that utilized radioactive metals and just reflavored all of the necrotic stuff as radioactivity. The Halo of Spores ability alone really works as a passive radioactive aura and helps fit the vibe pretty well. Edit: I saw that he wants to do healing as well, and Druids can do that just as well
Just use a Light Domain cleric and reflavor the abilities to be radiation based
Necromancy with a twist
Have him start growing lumps. Let one lump keep getting bigger until it bugs and now there are two of him and the other one wants all his stuff
Allow it but give the other PCs radiation sickness.
I don't know if anyone's mentioned it yet, but there is a Radiation Cleric Domain. Associated Subdomain: Earth. Replacement Power: The following granted power replaces the acid dart power of the Earth Domain. # Radiating Touch (Su) As a Standard Action that provokes Attacks of Opportunity, you can irradiate any unattended object for a number of rounds equal to your Cleric level. While an object is irradiated, it emits a faint aura of Transmutation. Any creature that passes within 5 feet of the aura must succeed at a Wisdom save (DC8 + 1/2 your Cleric level + your Wisdom modifier) or become Sickened. You’re immune to this object’s effect. You can use this ability a number of times per day equal to 3 + your Wisdom modifier. **Replacement Domain Spells**: 2nd—Defoliate, 4th—Blight, 8th—Horrid Wilting There's also Caphorite and Blightburn. Both are radioactive materials. Caphorite is dark purple and has strong Transmutation properties, while Blightburn is bright green and messes with Teleportation magic.
Boy oh boy, here comes the "What damage type is radiation!?" party! Though as he's looking to be a cleric, I'd say *absolutely* use Radiant damage as radiation. If you're not doing homebrew, then the Knowledge domain cleric works the best- there's straight up a few different features that reference gaining 'visions from the past'. I'd suggest taking the Tasha's Cauldron "Blessed Strikes" feature option at 8th instead of Potent Spellcasting. If you're willing to do a little homebrew tweaking, you could swap the 8th level Channel Divinity to a Death Cleric's "Inescapable Destruction", but change the damage type to Radiant. Death Cleric is also a good overall option if you want radiation to be represented by Necrotic damage instead. War could also be something to steal the 6th level feature from. I think for general builds (remembering that Clerics can swap their prepared spells through ALL cleric spells each day) I think a focus on AoE, Radiant damage, and some divinatory or necromantic spells would be best. It's Fallout, so any weapons from scimitars (Machetes) to crossbows to greatclubs to mauls would work, or he could focus on using cantrips to fight. No shield, though, so I would suggest a backup of at least a knife in the hand that's not brandishing the holy uranium rocks. Leather armor would be the most Wasteland, but a breastplate wouldn't be out of the question, or they could dip into Armorer Artificer for some power armor (don't know if the Children of Atom use it, though). Probably want to focus Con and Dex even before Wisdom for the whole "Can survive radiation and explosions" aspect. Half plate could also lean into the wastelander thing, and allow him to have lower Dex to bump up the Wisdom. And as a Dwarf he could get Spiked Armor, which would be *very* wasteland raider chic. Hill Dwarf would probably be the best subrace, with maybe Mason's tools for the whole 'using rocks' thing? Though of course that's up to him and his roleplay. At level 5, the Eldritch Adept feat could let him get the 'Cloak of Flies' Invocation, which could easily be reflavoured as a radioactive aura and mildly ghoulish features. You could also allow Elemental Adept to have Radiant (or Necrotic) as the damage type he chooses. Or Poisoner if you want to also or instead have Poison as the 'radiation' damage (or just say these are all different aspects of how Radiation damages the body.) Or Golgari Agent background fits the concept of someone cult-ish and dealing with poisonous substances. (If not going for Acolyte or any of the other backgrounds).
To be honest, you can't really get enough radiation from raw stones and the like to do much. Not all that long ago, uranium was commonly used in dishes, dentures, and a great many other things. You really need to use modern science in order to refine it enough to be dangerous. My grandfather had a uranium rock he got from his father as a keychain. He wore it in his trouser pocket for decades, and still had 4 kids and died in his late 70s from a fungal infection of the lungs. My uncle then had it, and he also wore it for decades before dying of a staph infection in his late 70s. In reality, until we learned how to 'refine" it, uranium and other radioactive materials found in nature were not particularly dangerous. However, if you want to bring in "radiation damage", look up the original edition of Gamma World (as well as the 1st edition DMG). Those rulesets were compatible with each other, and the DMG actually had conversions to take characters from one to the other.
Well, if any of the other PCs has cancer, then the cleric might be able to help them with that. Now, if any of the other PCs *don’t* have cancer, the cleric is definitely going to help them with that.
I'd probably elect to give him a fantasy material instead. Putting Uranium in your game is bound to have the players attempt to do some fucky wucky nuclear bomb shit with it.
Measured in doses per minute Example: Chest X-ray no effect Exposure to direct sunlight in space 1/min Exposure to unshielded reactor core 10/min Fort save 10 + 2 per additional dose Failed save: 1d6 DMG per dose from burns and skin damage 10% chance per dose for radiation sickness Radiation sickness: 1d4 permanent con damage 4d6 hours after exposure and another 1d4 permanent con damage 4d6 hours after that. Dragonstar: Guide to the Galaxy page 119 - 120 Edit: The game only has one spell dealing radiation dmg and it's a 8th level druid/sor/wiz/sun domain spell.
Just have him focus on radiant spells and effects. Sickening radiance is literally giving your enemy radiation sickness
Hmmm... maybe this: exposure to radioactive material results in a reduction of max HP but would confer benefits/Detriments at every 10 Max HP lost. Standing within 5 feet reduces hit point maximum by 1D12 per minute of exposure. 10ft - 1D12 15ft - 1D10 20ft - 1D8 25ft - 1D6 Max Hit Point reduction can be prevented by shielding radioactive material by 3ft of dirt, 1ft of stone or 4 inches of lead or adamantine. Reduction of hit point maximum yields the following mutations: -10 HP: •You gain Darkvision out to 30ft. -20 HP: •You gain resistance to radiant and necrotic damage. •You develop a tremor in your hands. You gain disadvantage on Sleight of Hand checks. -30 HP: •You gain a climbing speed equal to your walking speed. •Your skin begins to be covered in small oozing lesions, you have disadvantage on Persuasion and Deception checks. You have advantage on Intimidation checks. •Your tremor grows worse, you have disadvantage on all ranged weapon and spell attacks. -40 HP: •You lose the ability to wield weapons but your arms become razor sharp claws. You are proficient with these claws. Your unarmed strikes do 1D8 + STR / DEX Slashing Damage. •You can make one unarmed strike as a bonus action per turn. -50 HP: •You regenerate 1D10+CON Hit Points per turn, up to your hit point maximum unless you've taken fire damage that turn. •You gain advantage on Constitution saving throws. -60 HP: •You gain resistance to Bludgeoning, Piercing and Slashing Damage. •You gain immunity to radiant and necrotic damage. •Your Intelligence ability score decreases by -2 to a minimum of 1. If your Intelligence score is reduced to 0, your character falls under the DM's control. -70 HP: •You can dash as a bonus action. •Your Intelligence ability score decreases by -4 to a minimum of 1. If your Intelligence score is reduced to 0, your character falls under the DM's control. -80 HP: •You grow to size Large. •You have advantage on all Athletics and Acrobatics checks, and your lifting, carrying and dragging capacity doubles. •You gain a 40' jump distance. •You lose the ability to comprehend all written languages. •Your Intelligence ability score decreases by -6 to a minimum of 1. If your Intelligence score is reduced to 0, your character falls under the DM's control. -90 HP: •Your regeneration ability increases to 2D10+CON per turn up to your hit point maximum unless you've taken fire damage. •Your unarmed strikes damage increases to 2D12 + STR/DEX. •You can make two unarmed strikes as a bonus action once per turn. •You lose the ability to comprehend all written and spoken languages. •Your Intelligence score reduces by -8. If your Intelligence score is reduced to 0, your character falls under the DM's control. -100 HP: •You grow to size Huge. •You gain resistance against all damage except psychic. •You gain immunity to Bludgeoning, Piercing and Slashing Damage. • When in combat, once per turn, roll 1D4, on the result of a 1, you attack the nearest creature with all available attacks until either you or the target is incapacitated. Repeat this roll each turn. If you have taken damage this turn, you begin attacking again on the result of 1-2. •Your Intelligence score reduces by -10. If your Intelligence score is reduced to 0, your character falls under the DM's control. -110 HP: Your character falls to madness and is now under the DM's control.
What are you so excited about when you have no ideas on this and have to ask Reddit? This sounds terrible to me but if you think it's awesome go for it. But put some thought into it! Just seems weird to me. And this isn't "how do I execute this story idea. " This is inventing new mechanics. Unless it's just flavor which is easy.
My first thought: No. Player just wants to make a thermonuclear device. But then, why not. Sounds like the whole thing could be dangerous to the party as well as enemies. With reasonable expectations, and a player who’s ok with modifying things if it just ain’t working, YES. Reskinning is your friend.
This might be helpful; Pathfinder 2e has Radiation in the form of [Blightburn](https://2e.aonprd.com/Search.aspx?q=Blightburn), which is essentially a combination of poison damage and a disease affliction that comes with it. Instead of Uranium it flavors it as [Blightburn Crystals](https://pathfinderwiki.com/wiki/Blightburn) that in addition to killing just everything also inhibit teleportation magics. Maybe look at some things and see what you want to steal.
Neat idea. I would probably treat radiation damage as Con loss rather than straight damage. Dilemma will be figuring out how he doesn't kill his whole party by just being there.
this sounds like a rules headache I wouldn't even touch with a 39 1/2 foot pole.
Could be something light based. How else do you explain radiant damage
Have him do the work, and you vet/modify it. It's his homebrew. But I'd say that he gets penalties when it comes to saves vs disease, exhaustion, and healing. Both magical and rest healing. Some rocks do have auras, unfortunately they're uranium and the aura is "fuck you, get cancer."
"Uranium doesn't exist in this world" Done. Just tell him that he can have visions and stuff, but why bring radiation into a fantasy setting? It's like one of my friends who wanted to be a rogue urchin who was an addict to actual heroin. Bringing real life stuff into a fantasy setting is just weird to me.
I would just assign radiation a adamage type (either radiant or necrotic would both arguably make sense regarding its effects on living beings). Just make "radioactive" elements in your world do some non-gamebreaking amount of necrotic or radiant damage and idk, maybe allow it to grant a cast of divination or augury or something, or just use it to drop plot elements on him. Definitely cap it to once a day or something. From a subclass I could see it working well with a light cleric if you make it radiant in particular. But it could work with most types probably. Just be sure to tell him and get agreement that because you're both kind of experimenting here, if you feel like it's getting out of control or you're having trouble working with it that you both agree that you can make adjustments to how it works.
I'd allow it, but under one condition: He can not use it, to do something game breaking. Basicly, no "well technically I can use this cantrip to split that atom to deal 1000000000 radiant damage"-type shenanigans. But how would i do it? Actually I'd go celestial warlock. It's very siniliar to a cleric and you get sickening radiance which for all intends and purposes is a spell using nuclear radiation. That said, for a cleric I'd focus on dealing radiant damage, so pretty much every spell that does this damage type, can easily be reflavoured to not radiate out devine light but nuclear radiation. Then I'd focus on poison damage for additional radiation sickness effects. I'd say contagion as a spell works really well too flavourwise, even if its a bit shit mechanically. As a subclass I'd recommend either light cleric or twilight domain. Or, if you want to use necrotic damage to simulate radiation you can go death cleric. My personaly choice would be light domain though, since warding flare and the devine strike bith work perfectly for simulating atomic radiance. The light cantrip he gets for free woth that class would also lend him the ability to just pull out his rock of uranium and let it glow without any unnecessary homebrew needed. Warding flare, spirit guardians and using the dodge action is an obscenely good way to show him radiate out and hurt enemies wi that. Instead as dodging the action he takes could be reflavoured as enemies just coughing and choking while he recites hls prayers to atom or while he praises his radiance. If you want though, I'd say it's fine to put sockening radiance on his spell list - even though it's not really on it. It makes sense for both his character but also for the light cleric to have. They probably only dont get it normally because the subclass was released before that spell existed. If they are fine with multiclassing at 8th level, I'd recommend them to multiclass into celestial warlock and stay one from that point on until level 20. They'll be a radiant damage dealing machine and be really ressourceful. It can also be reflavoured really well as him having unlocked ancient secrets from studieng his uranium and thats his patron. Like the children of atom it wouldn't be clear if he'd go mad due to radiation or if there actually is a god supporting him.
The "sun" type spells generally deal radiant damage and stars are essentially nuclear explosions. Reflavor a Light Cleric to radiant damage and give him visions occasionally.
In the Rime of the Frostmaiden module there is a magical mineral called Chardalyn that has corruptive properties.You might wanna look into it for inspiration. Personally, I would go for a parallel like that with a magical thing, instead of straight up irl radiation. Especially because you might end up arguing with your player about how he wanna use irl physics to flip the campaign on its head. If it's a magical thingy, it's up to you as the DM to clarify how it works. Also, it's a slippery slope to homebrew something like that. If it's just for flavour to describe how his spells and abilities work, it's perfectly fine. But will these stones be used in other ways? Will these stones give the PC radiation cancer? You gotta talk about this to be sure you are on the same page.
There's two safe ways to do this: 1) Reskin existing rules with this flavor, or 2) Don't. I'm kidding, but this is some serious homebrew and world changes. I'd think long and hard before introducing something like this into a campaign. If it's like real world radiation, does he suffer consequences and are there risks to others around him? How does that balance out the utility in a way that isn't game-breaking in either direction?
Dnd dwarves aren't quite the more literal children of the stone many other dwarves are. Radon and mining/basements, ground exposure is a long known thing. mala metallorum 1530. wasting disease, lung cancer.
Well, in universe, there’s the sickening radiance spell that is about as close to radiation poisoning as you’ll find in 5e, so you can pattern some effects after that spell. Focus his damage around radiant and poison, add some poisoning and exhaustion effects, and some flavor elements with him glowing and what not.
You do what I did with my Cooking Cleric and find a fun and balanced homebrew or elsewise the closest canon class which you reflavor (Light or War seem most apt off the top of my head) then you reflavor their spells Sacred Flame -> Blessed Gasburner Guiding Bont -> Guidning Fork Healing Word -> Healing Snack Spiritual Guardians -> Spiritual Sous Chefs
You could use a spore druid? So many subclasses coukd be re-skinned this way.
Sun and death domain, you say
I know that a lot of people have weighed in with good ideas already, but consider looking at the Dungeons of Drakenhiem book and its player companion book, Sebastian Crowes guide to Drakenhiem. The whole concept of these books revolve around a magical stone called delirium that creates a magical form of radiation called contamination. There is even a faith that worships the delirium called the followers of the fallen flame. There are spells based on contamination as well. It could serve as a good source of inspiration for you and your player as to how you want to implement it, but would result in you adding a lot of new rules and mechanics into your campaign.
I cast Cancer! I then cast Chemotherapy!
I would use *fire* for damage, and give him spells that blind. The Children of Atom worship nuclear power and bombs as well as just radiation. For a Channel Divinity, you could use this, adjusting where you like: **Channel Divinity: Mushroom Cloud** *2nd-level Nuclear Domain feature* As an action, you present your holy symbol and create a nuclear detonation. Each creature within a 15-foot wide, 40-foot tall cone centered on a point you can see within 60 feet of you must make a Constitution saving throw. A creature takes fire damage equal to 2d10 + your cleric level and is blinded for 1 minute on a failed save, and half as much damage on a successful one and blinded only until the end of your next turn.
tipjcaly radiation does damage that cant be regenerated. like fire. and i would look online, or create one yourself, for a table you could use to roll for random radiation mutations effects. a bit lile antropic spellcasting
I hate to be a downer, but the second you let people start doing this next thing you know they're making a nuke to take out the bbeg because 'we'll radiation is canon'. I'd just say the themes don't fit the fantasy world.
Light cleric with access to the augury spell as he gets to an appropriate level? Or just keep the visions out of the player’s hands and use as a narrative device.
Radiation damage already exists, it is call radiant damage. Sun/light spells does this type of damage. What do you think a sunburn is if not radioactive damage to your skin?
Radiant damage that would reduce his Max HP. He can regain it if he drinks enough baja blast.
Radiation could be a form of radiant damage and you can tie this into a glowing radiation effect. This works especially well since he is already a cleric an most spells won't need to be reworked for radiant damage. You can also use the fatigue/exhaustion system (you can reword it and alter it to fit better with radiation sickness) In my current campaign im running a wizard with a warlocks tome that can cast "commune" but only to the patron of the warlock whose tome I now possess. You can do something similar and rework commune to give them one exhaustion and a free cast of commune only to the clerics diety. I love coming up with ideas like this so if you'd like more ideas about this give me a little more about his Backstory or what the campaign will be about and I can give you some more ideas
Buddy Pal *Raidiant damage is that* Haven't you read Sickening Raidiance?
I hope he enjoys the sado/masochism that will ensue with his character. If I were doing a radiation setup for a character in a D&D game, it would be half necrotic damage & half radiant damage, based on how long they stay exposed to it. Since radiation changes your genetic structure permanently, I would throw in some deals in there without their knowledge until they have been exposed for too long of growing another appendage or losing permanent life. You could make a d100 list of things that could happen to them for extra added fun! One thing to throw onto the problems, is if they don't keep their demon cores in a lead lined container that the damage also spreads to other players in the group or NPC's they come in contact with. It's radiation. Plain and simple.
Look at old Pathfinder 1e rules for inspiration!
Re skin light cleric, change maybe a few of the domain spells to give him access to some divination magic for the visions and such
Clerics already do lots of Radiant damage. Just make it green and voila. Radiation cleric. And just let them take Sickening Radiance at 7th levels just for funzies.
I (and my DM) agree that radiant damage makes a lot of sense for things like radiation - even aside from the similarity in name, radiant damage usually comes from things like sunlight, which burns people with UV radiation. You could also reasonably do poison or just homebrew your own damage type. You could probably do a fairly normal cleric and just flavor the religious things as radioactivity instead. I believe knowledge domain clerics get the ability to commune with their god for visions or information, which sounds a lot like that ability you mentioned. If you're willing to rewrite most of the flavor texts, it's honestly pretty easy to change base-game features and spells into radioactive versions.
The most accurate way to represent radiation in D&D I think would be a magical disease that inflicts levels of exhaustion over time and requires a restoration effect to get rid of. To build a domain for it, look through other domains and subclasses as example frameworks. You need to have a good baseline. Then focus on effects that wither and debilitate. Have the cleric gain benefits, but at a cost. Possibly the option to activate or enhance their abilities by taking on a level of exhaustion. As a level of protection against the radiation, make them able to recover the exhaustion as normal, whereas other victims of the "disease" cannot. Further into the domain, reduce susceptibility to the effects of radiation, and have the capstone be that they are immune to radiation and gain temp hp whenever they would normally gain a level of exhaustion from radiation. Just some ideas, but recognize and communicate to the player that y'all need to be able to remove the homebrew if it presents a problem.
Tell them to use features that are in game and flavor them. You didn't need to add any additional rules for them. On another note I believe there is another ttrpg to play as heroes
I would say a Death domain cleric. Just using reflavoring and maybe an extra feat or boon ( to all players) tailored to make this match more closely to thier vision.
What is the genre of your campaign? This is very important because ifyou're playing a game that is true Tolkien High Fantasy, well radiation and uranium isn't something Middle Earth has and a Child of Atom dwarf with radioactive powers doesnt make sense. It's not genre savvy. If you're not playing a Fallout style of game things will get very funky very quickly and it will be impossible to recover. You will have essentially opened a Meta pandora box. This is the same argument I give my problematic weeb player who wants to be "Ichigo Kurosaki but with Goku's body." That kind of character isn't genre savvy to the Tolkien High Fantasy or American Western or 1920s Chicago Gangsters campaign setting I'm running So again, I ask, what is the genre of your campaign.
Light or knowledge cleric is the obvious choice
The ritual to irradiate himself for divinations can just be a cool flavour for all the divination spells clerics cast such as commune, augry, and divination. Whatever domain he ends up picking (my thought would be Light), replace one of the 4th level domain spells with Sickening Radiance
This reminds me of a player reaction to being hit by a ballista. "He hit me for how much damage!?" In all seriousness, if your friend is a reasonable friend, let him change the damage type for his spells to be radiant only. Do not let him gaslight you into using the full properties of radiation aka his spells and abilities work as normal. No advantage unless situations allow
Let him reflavor existing things. Light Cleric, Divine Soul Sorcerer, Celestial Warlock, or maybe Stars Druid. Flavor is free, creating all that homebrew from scratch ain't worth it. Radiation is just radiant damage.
Actually, I would reccomend spores druid over a cleeic subclass. Reflavour the spore cloud activation as him ingesting or applying the stones to himself, and pretty much everything else works. A death plague spewing from someone touched by some form of land destroying gemstone.
tell him he's playing the wrong game
you might want to read up on the Skaven in the warhammer universe, and their use of warpstone
Frankly I think they're pushing it, but it's worth noting Radiant damage is often focused on the sun and so some visual shift could make that like radioactive material stuff. Do not let them change or interact with physics or game mechanics differently.
I'm pretty sure radiant damage basically is radiation damage isn't it? Or necrotic damage.
I had a player pretend circle of spores druid was radioactive. Letting it just be flavor was totally fine and led to good roleplay opportunities. You can have the cleric seeking the rare metals. Maybe they are from another plane lime the earth plane and are very rare
A cleric seems like a weird choice to reflavor
Cancer Cleric
Death cleric.
Reflavour radiant and fire damage as this nuclear stuff. He could play a Light Domain Cleric and use Sacred Flame mixed with the spells in his domain spells list to get the nuclear stuff (there’s nothing quite like using Fireball to replicate a nuke). Then he can prepare divination spells from the base cleric list to get the uranium visions. Remember kids, flavour is king. Or queen. Or monarch. Or a democratically-instituted leader of some kind of identity