Cain, Firstborn of Eden

Menace.
Rampage 2.
Whenever Cain deals combat damage to a player,
you may sacrifice another creature. If you do,
put X +1/+1 counters on Cain, where X is the sacrificed creature's power.
Whenever a creature dies, you may pay {1}{b}{g}. If you do, draw a card and lose 1 life.