Fyodor was the leader of an underground organization called the Rats in the House of the Dead, and was one of the five members of the Decay of the Angel. His goal was to find the reality altering book that's hidden deep within Yokohama to use it and rid the world of all its ability users. Because of his very high level of intellect, Fyodor was one of the most difficult opponents the Armed Detective Agency has ever faced. He has failed his goal and has given up on it completely.