a unit starts/finishes casting an ability
ability equal to your spell
^^^and that above^^^^
im a noob so im probably wrong.
EVENTS: Unit - Unit starts the effect of an ability
CONDITIONS: (Ability being cast) equal to (CRIT THING)
ACTIONS: Set (ThisIsAnIntegerVariable) equal to (Random number between 1 and ([B]100/([I]Percent chance to crit[/I][/B]))
If - Then - Else (Multiple actions)
IF: ThisIsAnIntegerVariable is equal to 1
THEN: Cause (Triggering unit) to damage (Target unit of ability being cast) for (DAMAGE) damage
ELSE: Do nothing