Captain Calan is a high ranking Providence agent. As one of White Knight's most trusted agents, he is usually tasked to implement his last-resort plans when it appears that Rex cannot complete the job himself. Calan is also in charge of the daily briefings given to Agent Six, Rex, Dr. Holiday, and Bobo Haha.
During a normal day at the Keep in which Rex along with Noah tried to convince Calan to let them steer the ship, Van Kleiss started an ambush. After the long struggle Captain Calan was seized by Van Kleiss and turned into an E.V.O. As a mindless creature he remained in the Pack until he was cured by Rex.
In Master of E.V.O.s, he is uncured and transformed back into an E.V.O.