Radiation Damage

I've been chewing on an idea for radiation, its damage, and the sickness caused therefrom, for my game ... for reasons ... mostly involving the Star Things currently descending over the Greyhame Mountain region.

The first glimmering of this idea came to me through listening to episode 9 of "The Hall of Blue Illumination", a podcast dedicated to M.A.R. Barker's Tekumel setting; around the 1:20 mark (first link, episode 9), Victor J. Raymond mentions radiation damage and how Barker adjudicated that neither cure disease nor neutralize poison spells worked against its effects. What its effects were, alas, we know not--but the idea of radiation as a separate damage has stuck with me over the past few months ...

So anyway, I've got some super-secret write-ups for monsters and spells that cause radiation damage; this damage will apply to hit points as normal damage, but has the added effect that after certain thresholds, the damage causes "radiation poisoning/sickness." Trouble is, what's the threshold?

The chart on Wikipedia for "Whole Body Absorbed" Grays (Gy) seems like a good place to start, given its clear number values and possibilities for nausea, headache, and mortality. Unfortunately, the chart jumps from 1-2 Gy absorbed with 0-5% mortality, to 2-6 Gy with 5-95% mortality! Admittedly, this mortality is over the course of weeks; but dealing 3 damage to a character and having them die ~50% of the time after several weeks regardless of level ... just doesn't seem sporting.

So let's assume 1 radiation damage = .5 Gy (half a Gray). It can still be lethal pretty quick (6 such damage gets one to the "50% mortality in a few weeks" range), but still allows concrete understanding plus the possibility to run away really fast / put something between you and it really fast.

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Radiation Effects

1) up to 2 radiation damage: sunburn, no other side effects

2) 3 to 4 radiation damage: save v. poison at +2 or nauseous all session, at end of session save v. poison or at -1 on all rolls for 1-4 weeks

3) 5 to 12 radiation damage: save v. poison or nauseous for 1-4 weeks, at end of session save v. poison or die in 1-4 weeks; successful save indicates survival, but nausea continues additional 1-4 weeks (i.e. 2-8 weeks of nausea)

4) 13 to 16 radiation damage: save v. poison at -2 or nauseous for 1-4 weeks, begin vomiting and otherwise incapacitated by severe headaches in 1-6 turns; at end of session save v. poison at -2 or die in 1 week, successful save indicates survival, but incapacitated for 1 week, nauseated for 2-8 weeks after that

5) 17 to 60 radiation damage: save v. poison at -4 or confused per the spell by nausea and severe headaches for remainder of session; at end of session, save v. poison at -4 or die in 1-3 days, successful save indicates survival but with 2-7 weeks incapacitated by sickness

6) 60+ radiation damage: save v. poison at -8 or die in 1 turn; success indicates that death is staved off 1-6 turns, but the character is confused per the spell for their last few turns

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There should probably be additional debilitating effects of radiation sickness after, but I'll admit, I'll probably be more generous than Barker as regards spells like neutralize poison etc. curing radiation damage.

Still, we'll see. This is a rough draft. It hasn't actually presented itself in my game yet ... yet ...