Encyclopedia Entry:
A demonic knight with a grotesque figure, its head has been severed from its body. It inhabits the demon realm. Because of its identifying feature, it’s also known as the “headless night.” They are the prized avant-guard of the demon lord’s knights. They are extremely loyal, and possess exceptional military prowess. In the schematic shown here, they hold their head with their left arm, but most of the times they appear, they put their head on their body, so it’s often hard to even realize that they’re dullahan.