Background[]
Kako is part of No.1 of the School Mysteries along with Mirai and Aoi Akane, and presumably seen as the leader of the three. He is a supernatural that controls the past of the school with abilities that go as far as to reverse the effects of the other two No.1's. He is also one of the oldest School Mysteries, seen by his appearance, wisdom, and elderly tone. Although he listens under Hanako-kun's command, who is established as the leader of the School Mysteries, he offers advice and inquires about the state of the school, to which Hanako-kun states he's worrying too much.
Relationships[]
Mirai[]
Mirai seems to be close to Kako, referring to him affectionately as "Ojii-chan", and Kako sometimes carries her in his arms. Several years ago, Mirai worked with Kako to recruit Akane as one of the Clock Keepers, by using her powers to stage Aoi's near-accident while Kako spoke to Akane. To prevent Mirai from using her powers, Kako usually keeps Mirai in their boundary, though she escaped from him once, triggering the events of the Clock Keepers Arc.
Aoi Akane[]
Akane does work for Mirai and Kako under his contract with the Clock Keepers. As Kako appears not to have a name, Akane calls him Kako (literally meaning "past" in Japanese) or more derogatorily as "that rotten old man".
Hanako[]
Though Hanako is the leader of the Seven Mysteries, the Clock Keepers (presumably led by Kako) refused to see him again or tell him the location of their boundary after their first meeting. However, Kako still obeys Hanako's instructions, as seen when Hanako told him to reverse the school's time to before Mirai's escape.