Soul Cairn

Whenever a creature dies, put a soul counter on
Soul Cairn.
{t}, Remove a soul counter from Soul Cairn: Add
one mana of any color
{2}{b}, Remove 3 soul counters from Soul Cairn:
Create a token that' a copy of target creature in
your graveyard. Exile it at end of turn.
"You give the Ideal Masters souls, they give you powers
to summon the undead. It's all very business-like."
-Serana