do so until the end of the series. Aozaru is the physical manifestation of the sentient spirit of the scabbard of the . The sword is a royal treasure to the kingdom of Kei and can only be wielded by the kingdom's rightful ruler – as such, Youko is the only one who can draw the sword from its sheath. The sword was forged from a water demon that a previous great ruler of Kei had defeated while the scabbard was created from a long-tailed monkey demon. From the scabbard hangs a large jewel that can heal the one who holds it. The sword is not only capable of killing demons and sages and breaking substances like metal chains, but is also capable of presenting visions of the past, future, and things in the distance. The sword and scabbard must be kept together, otherwise the phantasms of the sword appear unchecked while the spirit of the scabbard is free to act as it wishes. When Youko loses the scabbard during an attack by Kikis, it appears in the form of Aozaru, the blue monkey, and taunts her with her doubts while the sword presents her with visions of things she does not wish to see. Eventually, Youko, overcoming her own doubts, kills the monkey and picks up the dead scabbard. Because she has killed Aozaru, the sword can be drawn from the sheath by anyone, though it can be wielded effectively only by Youko. Seikyou has long served as the Chosai, the top administrator, of Kei. Seikyou works to convince Youko that Koukan, the leader of the province of Baku, is a threat to her. After an assassin plots to kill Youko, Seikyou advises Youko that Koukan planned it and that she should execute him, but Keiki advises her to listen to Koukan before acting. When Youko orders Koukan to report, Seikyou has him attacked, forcing him to flee. Seikyou continually seeks to confuse Youko, telling her that Gahou is corrupt but advising that no action be taken against him, even though Seikyou secretly supports Gahou. He repeatedly seeks meetings with her when Keiki is not present so that the kirin cannot advise her. Youko, citing Seikyou's attempts to manipulate her and his failure to better safeguard her life, demotes Seikyou and appoints Keiki as chosai. When Youko leaves to study with Enho, Seikyou takes advantage of the situation to