Keeper of Death

Flying, Deathtouch, Shroud
Whenever this creature dies, create a Blue 1/1
spirit creature token with Shroud and "{5}{u},
Sacrifice this creature: Return Keeper of Death
from your graveyard to the battlefield."
Whenever this enters the battlefield, conjure a Hyrulean Knight to the top of your library for
each Hyrulean Knight in your graveyard.
(Minimum one)