Messiah (メシアMeshia?) is the originator of all Horrors from the True Demon World (真魔界Shin Makai?) and existed since the beginning of the conflict between Makai Knights and Horrors. Messiah is the most unusual Horror because she's the only Horror that appears almost perfectly human in form, resembling a giant white-skinned half-naked woman with long-clawed fingers and unique jewelry and tattoos around her head and shoulders. Her back contains a Taoist round disc.
Though Messiah longs to enter the human realm, despite all her powers she cannot cross through without a large source of energy. After sensing Barago's desperation for power, Messiah reveals herself in a Madō Book that contains forbidden techniques. Though only a shade, Messiah offers to give Barago knowledge and power of the forbidden Makai methods in return to bring about the legend of Kiba. Barago wholeheartedly agrees to give up his soul for power and Messiah proceeds to start him on his path of destroying lives to set up the conditions to summon her in her full glory through Kaoru, who is a suitable vessel due to the conditions of her age and birth.
But once he fulfills his part in her summoning, removing any trace of humanity in him, Messiah absorbs Barago using Kaoru's body as a medium upon being awakened to use his power to complete the process. Her plans to reach the human world are foiled by Kouga, who enters her realm and defeats her with spiritual help from Kaoru. She is ultimately defeated when, overconfident with her powers, she runs his sword into her head and releasing Kiba in the process as she is forced back into her dormant state.
Her powers include ultra-human strength, high combat capabilities (while possessing Kaoru), magical shielding, magical energy attacks, able to summon Horrors by merely touching the ground she walks upon, and flight. The full range of her powers were never revealed, suggesting she has a larger range of combat capabilities.