Dreimo Hellsong

Tribute X, where X is the amount of damage
your opponents have taken this turn (As this
creature enters the battlefield, an opponent of your
choice may put X +1/+1 counters on it.)
When Dreimo Hellsong enters the battlefield,
if tribute wasn't paid, reveal the bottom card of
your library. If that card is a Demon or Devil,
you may cast it without paying any of its costs.
"My demands are trivial. I cannot say the same of
my master."