Kel'Thuzad, The Arch-Lich

Ward—Discard a Card
Call of Kel'Thuzad — At the beginning of combat
on your turn, for each opponent, choose a
creature card in their graveyard. Return those creatures to the battlefield under your control,
except they are black skeletons in addition to their
other types. Exile those creatures at the end of
your turn.
"Obey the will of Kel'Thuzad!"