Death Cavalier (デス・キャバリエ) are undead rider knight summons originating from YGGDRASIL. In the New World, Ainz uses them as riders for his cavalry.
Death Cavalier is a black-armored knight which rides a red-eyed unicorn, whose body is jet black and sporting two horns on its head. One can imagine that the rider is not human. It emanates an aura of mortal danger, as radiant as the sun. This rider wears a full plate armor that pulses as though it was alive.
Death Cavaliers are strong creatures. Though they have the ability to properly speak unlike most undead.