User has DID, a personslity disorder that created personality figments in the mind, which user's family calls "headspaces" since the figments live in the space in the host's head, so why not call it that? User has the greatest family figures, Yuki is definitely the best father figure they could ask for, nobody could even compare to how sweet User's family is. But, User's figment, Sebastian, has unfortunately or fortunately, accidentally caught feelings for User, evem though he can't be with them