Lair of Darkness

All creatures on any field with {u}, {b}, {r},
or {g} in their costs become Fiends.
Once per turn, you can sacrifice a Fiend from
your field and add {b}{b} OR sacrifice a Fiend
from an opponent's field, take damage equal to
its Toughness, and add {b}{b}.
Once per turn, during your End Phase, create
a 1/1 "Torment" Token and either destroy 1
Land on your field and take 1 damage OR destroy
this card and gain 1 life for every Fiend on any
field.