"What do you think I am, some kind of item factory?"

Responsible for finding the Moon Senshi and informing them of the need to kill Lady Serenity in order to prevent the reincarnation of Queen Diana, Kouken knows little else about his past or his mission. The prismatic disc on his head is the only clue to his origins; he has no memory of who sent him to earth or even why he knows of Diana's imminent reincarnation.

Despite this, however, Kouken seldom lets the mystery of his past or the minutia of his mission trouble him. More likely to trouble him is his primary charge, Tokimo, who treats him more like a convenient repository of magical items than a valued guardian and assistant. Still, he and Tokimo have something of a teasing friendship, and Kouken agrees with Sailor Charon when she decides that the fight against Sailor Pinkmoon needs to be called off until the Moon Senshi have defeated Nemesis--after all, unlike Seisui, Kouken's does not only a personal vendetta against the royal family--his reasons for fighting them are purely practical.