The Eternal Servant

{2}{b}{b}{b}, {t}: Return target creature card from your graveyard to the battlefield.
When The Eternal Servant dies, create a legendary artifact token named Phylactery Crystal. It has "{2}{b}, Pay 2 life, Sacrifice a creature, Sacrifice Phylactery Crystal: Put The Eternal Servant from your graveyard to the battlefield tapped."
Death will not free you from his servitude.