Nacht Faust

The Black Bulls' secret vice-captain and a spy inside the Spade Kingdom: four devils on a leash and Shadow Magic to come and go from the Underworld.

Nacht has made pacts with four devils — Gimodelo, Slotos, Plumede and Walgner — and uses them in Devil Union as living weapons. He hated himself for years after his twin brother Morgen's death, and lived for years as a traitor in everyone's eyes in order to infiltrate the enemy. He is the one who teaches Asta that a devil is not dominated: it is bargained with.