Eris, Corrupted Witch

Swampwalk
Every land with a corrupt counter is a swamp.
{b/g}, {t}: Put a corrupt counter on target land.
{b}, {t}, sacrifice Eris, Corrupted Witch: Search
your library for a Demon or Devil card, put that
card onto the battlefield, the shuffle your library.
You lost life equal to that card mana coast.