Razaketh, the Foulblooded
{5}{B}{B}{B}
Legendary Creature -- Demon
8/8
Flying, trample
Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.
Yawgmoth, Thran Physician
{2}{B}{B}
Legendary Creature -- Human Cleric
2/4
Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)