Baron Sengir, Conqueror

Whenever Baron Sengir enters the battlefield,
Amass Creatures of the Night 8.
Whenever another nontoken creature dies,
Amass Creatures of the Night 2.
Creatures of the Night you control have flying
and trample (Creatures of the Night are Vampires, Skeletons and Zombies).
Empires rise and fall, but Sengir is eternal.