** spoiler alert **
In this volume, we find out that the mysterious man watching the White Feather Kids battling the Kekkaishi at the end of the previous volume was really an ayakashi in a human skin disguise who is working for another mysterious ayakashi called Master Byaku who is collecting information on the Kekkaishi for some sort of project. A few days after the fake human disappears, another mysterious boy joins the school. He was sent by the Shadow Organization, specifically by Masamori, to gather information and assist the kekkaishi. His name is Gen Shishio and he is half-ayakashi, and he notices that he and Yoshimori fight the same (improve in the midst of battle and adjust their fighting style/tactics accordingly). We see a bit more of Master Byaku talking to a mysterious female ayakashi, who seems to run their organization and wants to take possession of the Karasumori site ASAP.