Harkon, Ascended King

Flying, haste
At the beginning of each end step, if a player
was dealt damage by three or more Vampires
this turn, each player sacrifices a creature. If you
sacrifice a non-Vampire this way, transform
Harkon, Ascended King.
"Scions of the night! The prophesied time is upon us.
Soon we will claim dominion over the sun itself, and
forge a new realm of eternal darkness."