Demon of Death's Gate

You may pay 6 life and sacrifice three black creatures rather than pay this spell's mana cost.
Flying, trample

Pestilence Demon

Flying
{B}: Pestilence Demon deals 1 damage to each creature and each player.

Kaalia of the Vast

Flying
Whenever Kaalia of the Vast attacks an opponent, you may put an Angel, Demon, or Dragon creature card from your hand onto the battlefield tapped and attacking that opponent.

Bloodgift Demon

Flying
At the beginning of your upkeep, target player draws a card and loses 1 life.