Mourn the Lost Souls

Whenever a creature an opponent controls dies,
you may pay 2 life. If you do, exile that creature.

Pact — Whenever a creature becomes exiled, you
may gain a debt counter, then pay {b}{b} for
each debt counter you have. If you do, return
that card to the battlefield under your control.

The poor souls enter the Blessed Sleep, only to be
ripped away into the mortal world.