Tathamet

Flying, Trample, Deathtouch.
At the end of any player's turn if Tathamet, Evils Origin is untapped, and they control no creatures, they lose the game.
{x}{t}: Destroy X of target Player's Creatures.
"Tathamet was his name - and he breathed unending death and darkness from his 7 devouring heads. The Dragon was solely composed of Anu's cast-off aspects. The end sum of the whole became a singular Evil - The Prime Evil." - Book of Cain.