Along the way, Shugo and Rena befriend Mireille, a rare item hunter; the fierce Ouka; and Hotaru, a peaceful girl. While waiting for an event to start, they encounter a strange girl named Zefie, who is lured to Shugo because she believes the bracelet smells like her mother, Aura. It is later realized that Zefie is a vagrant AI – an AI that acts independently outside the parameters of the game. Zefie's presence upsets many, including the Cobalt Knights, a group of administrators that follow the rule "If you can't control it, delete it" to an extreme.