Heroic Sacrifice

Before starting the game, exile Heroic Sacrifice
from your library face down.
As an additional cost, sacrifice a creature you
control. Destroy all creatures you don't control
and deal 5 damage to all opponents.
Fateful Hour - If you have 5 or less life and Heroic Sacrifice is in exile, you can pay {w}{r}. If you do,
put Heroic Sacrifice in your hand from exile.
Activate this ability only any time you could cast
a sorcery.