Igor Neuhaus is an Upper First Class Exorcist as well as lecturer at the True Cross Academy. He is also a survivor of the Blue Night.
Igor has brown, long hair, as well as pale skin. He wears an eye-patch over his left eye, which was burned out during the Blue Night when he was possessed by Satan. He wears the standard Exorcist uniform, a full black coat with black pants. He also keeps bandages on his fingers and arms, which contain summoning tattoos underneath.
Due to being possessed by Satan during the Blue Night, Igor lost his left eye to Satan's blue flames, as well as his family when he killed them under Satan's influence. Because of this, he hates Satan immensely, as well as any Demons related to Satan. He seems to believe that as Satan's son, Rin can only be evil at heart and must be destroyed no matter what. Ironically, he is extremely loyal to Mephisto, another one of Satan's sons, and was able to put aside his hatred for Rin and stop attacking him when Mephisto asked him to.