Kaihrhos, The Vengeful

Deathtouch, Lifelink, Flash, Undying, Flying, Demonic Essence 12

If an ally Greater Demon was destroyed and Kaihrhos is in your graveyard, you may choose to immediatley summon him. If you do, reduce the Demonic Essence Cost of Kaihrhos by 4. If the Destroyed creature was a Son of the Fourth Circle, you may instead summon him for Free

The first creature destroyed by Kaihrhos each turn is exiled.