Is there a way that you can damage a certain unit in a trigger? Like ( Damage 30% Of Unit Life). Not like set unit life to 50% or Set life to value. If you can help, thanks.
By changing units life manually you don't actually "damage" a unit. instead you should order the [attacking unit] to damage the [attacked unit] with 0.30 (=30%) times the remaining life (or maximum life) of the attacked unit. Hope you will find the triggers by yourself, if not post it here asking again.
@Inu Yasha: Sp4WnEd did exactly not want to do what you proposed..
ordering a unit to damage another unit via this trigger instantly deals the damage, without any effect or cooldown or something like that. if you want to damage a unit this way, you always need an "author" of the damage, thus the unit damaging it in the trigger.