|Given Name||The Dullahan|
The Dullahan first appears in the fifth book when Valkyrie tries to save one of his victims. She attacks him without harming it.
Later, the Dullahan is summoned by a Banshee to take Valkyrie to Nye. The Dullahan has to leave and tells Nye, making sure that it agrees to not do any experiments on her.
The Dullahan is impervious to magical attacks and very strong physically. Despite being headless, the Dullahan can still communicate to other beings, though it is unknown exactly how. It is also unknown how a Banshee summons it, but the Dullahan "spoke" to Nye before leaving it with Valkyrie.