Kako/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.