Yukora, the Prisoner
Betrayers of Kamigawa — Rare
Legendary Creature — Demon Spirit
When Yukora, the Prisoner leaves the battlefield, sacrifice all non-Ogre creatures you control.
It took ninety-nine monks to weave the spell that trapped Yukora. Upon the death of the ninety-nine, the spell was broken, and the demon returned to the mortal world seeking vengeance for its imprisonment.