Diablo, Prime Evil

Bestow {7}{b}{b}{r}- (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Indestructible
Diablo, Prime Evil and
enchanted creature gets +1/+1 for each time a player loses life and +1/+1 for each black creature you control.