Amanojaku
Amanojaku is a powerful entity that, long ago, was sealed by Satsuki's mother in a tree in the mountains, but was finally released from his magic prison due to urbanization. However, he did not have his freedom long, as Satsuki sealed him (by accident) in the body of her pet cat, Kaya. At first, Amanojaku is hostile toward the kids and takes great pleasure in seeing them in trouble, but throughout the series he develops somewhat of a care for them, especially for Satsuki and Keiichirou.