Someone asked about doing Dark Sun with DCC on G+, earlier today – this is a thing that’s comes up before and will come up again. From it, though, I noodled through what I think might be an alright mechanic to model the Preserver / Defiler casting mode Dark Sun is known for.
Wizards – Preserving / Defiling
When a wizard casts a spell, they must determine if they’re Preserving or Defiling.
Spell checks are 1d10 + (Caster level) + (Int modifier) + (Spellburning). Luck cannot modify this roll.
When Preserving, a roll of a 1 is “Lost. Failure.” Spellburn functions normally per the book.
When Defiling, a roll of a 1 is “Lost, failure, and worse!” Spellburn does not function as normal.
Instead, the caster spellburns from lifeforms around them: they first determine how many points they wish to spellburn. 1d3 * that number is drained from any nearby creatures, evenly distributed (and randomly allocated as necessary). If an insufficient number of ability points are “available” to be spellburned, 1 square meter of earth will be killed and rendered unable to sustain plant life for each ability point shortfall (these will be the closest square meters to the caster that have not yet been killed).