Cassian is one of the lower members of Delilah. Although he has the body of a child, he is actually thirty-five years old. As a child, he was given to a circus by his parents. He joined Delilah for the purpose of getting an adult body. In the organization, Cassian works for Jizabel. Despite not liking the man at first, he grows to care for him over time. When Head Priest Cassandra attempts to kill Jizabel, Cassian jumps in the way and is critically wounded. Jizabel grants him his wish by giving him that mans body and lets him run form the evil clutches of Delilah. In the moment of his departure Cassian vowed to come back and save Jizabel from Alexis.
Cassian leads Cain to the Tower in the final volume just in time to see Jizabel fall from the balcony. He is last seen burying Jizabel in some forest area and commenting that the doctor will never be lonely in such a place.