An exorcist dispatched from the Vatican to exterminate a demon in Domremy village. Nicholai is the head of a powerful group of priest knights, although this is not revealed. Under the command of (Bishop) Gregori, they have undertaken many secret activities. Within the powerful knights, Nicholai is the only one to obtain permission to use the Mistletoe. He was previously assigned to assassinate Albert Simon by the Heresy Inquiry but Simon was assassinated by someone else first. Now Nicholai is investigating the murder to discover the identity of the real killer.