Tainted Blood

This is a self-buff the Felhunter can cast (instant-cast, no cooldown, 1-minute duration) that reduces the Attack Power of anyone who strikes it directly with a melee attack.

Every enemy that hits the Felhunter directly with a melee attack acquires a debuff reducing its Attack Power for 10 seconds, and this debuff can stack up to 5 times.

This ability can be set to auto-cast; if so, the game's AI will automatically have the Felhunter cast Tainted Blood on itself whenever it enters into combat. It incurs a mana cost only when the Felhunter casts it; it doesn't use any more mana no matter how many hits the Felhunter takes.