Izuna is also the one to teach Sol Badguy and Sin how to use the tactics of the Ghost and Master Ghost system in the game as well. Most fans believe Izuna's looks were taken off of Slayer, though this is not likely because in various interviews with Daisuke Ishiwatari he exclaims that Izuna along with Valentine, Dr. Paradigm, and Sin are all new children (creations) of his.