16% of Base Mana 100 yd range
When active, 20% of all damage taken by the caster is taken by your Imp, Voidwalker, Succubus, Felhunter, Felguard, or enslaved demon instead. That damage cannot be prevented. In addition, both the demon and master will inflict 5% more damage. Lasts as long as the demon is active and controlled.
whats not to like about it?