Magic Corruption Rules

[athornton]

For my Vornheim/Gaxen Kane game. Draft 1. Subject to change.

Each time an M-U spell is cast, caster must roll:

SL = "Spell Level"
CL = "Caster Level"

(SL ^ 2) / (10 * ( CL + 1 ) )

Round that fraction to the nearest 5%, and caster must beat it on a D20. 1 is always a failure, 20 is always a success.

If the roll fails, the caster must make a saving throw vs. magic with a penalty of the spell level (so, -1 for a first level spell, -3 for a third level spell, etc.)

If *that* saving throw fails, roll 1d6. The demon powering the spell:

1-3) devours 1dSL from a random ability score
4-5) devours 1dSL maximum hit points
6) confers a mutation: roll on the d100 mutation chart from http://monstermanualsewnfrompants.blogspot.com/2011/12/1d100-table-of-mutations-and-wait.html


We can also use this for "overcasting" ; each time you cast a previously-memorized spell no longer in memory, it is treated as if you added the spell level to the effective spell level.

Thus: you're a first level magic user with _Magic Missile_ memorized. You cast it. That creates a 1/20 chance of something bad happening.

Then, you cast it again: it's now an effective level of 2, so there's a 4/20 chance of mishap. Your third try? 9/20....and your saving throw penalty increases too.

And...you can do this for learning and casting spells too hard for you at your current level, as well.