It seems like I might be right. Both foxes, Kuzunoha and Tensei, were the two big foxes at the start of the arc where Seimei met when he was a child. I wonder if he was thinking that he was helping the foxes make a town for the kitsunes to live in. He used both Kuzunoha and Tensei as gate guardians. One inside Kuzunoha and Tensei on the outside; however, Seimei being Seimei more or less traped majority of the kitsunes in the town. Maybe only the strong ones can escape the town. Maybe Tensei wants Haruaki's body so he can use Haruaki/Seimei's power to destroy the seal on the island.