Purify

Resist Chance

clamp(
  target.fireResist × 0.0005
  + clamp((target.level − caster.level) × 0.005, −0.1, 0.1)
  − caster.accuracy
, 0, 0.9)

Cleanse Mechanics

Only affects debuffs of matching type. Some debuffs cannot be cleansed. Cleansable debuffs start with 3 counters and are removed when counters reach 0. Debuffs with no resist are always removed in a single cast. Otherwise cleansing removes 1 counter guaranteed, plus 2 independent chances to remove 1 more each (blocked by the debuff's cleanse resist). DoT damage reduced while partially cleansed (2 counters → ×0.9, 1 counter → ×0.8).