Kako

Kako (カコ / 過去) is a supernatural who controls the past as one of the three Clock Keepers, along with Mirai and Akane.

Appearance
Kako is an old man with a long braided beard (with a bead-like golden ornament near the end), mustache, and slicked-back hair.

Kako has an asymmetrical owl-like mask with a long hooked nose, similar to Akane, which he does not take off. He uses a cane that resembles the hands of a clock in his right hand. Though Kako appears to be somewhat hunchbacked, he is taller than even Akane.

Similar to the other Clock Keepers, Kako has a pocket watch with a chain, though the clock face appears to be inversely colored compared to Akane's, with light lettering against a dark background. Kako typically holds this pocket watch in his left hand, sometimes storing it within his right sleeve.

Kako wears a long dark cloak with a hood, which is light-colored with a pattern of small triangles on the inside (presumably in similar colors to Akane's, though it has not been shown). On the front of the cloak, there is a golden braid between two tassels at the lapels; Kako's cloak is completely closed, unlike Akane's. Kako also appears to be wearing a dark collared shirt under his cloak, though it is not clearly shown.

Personality
As the oldest among the Clock Keepers, Kako acts as their de facto leader.

According to Akane, Kako is more reasonable than Mirai, but he still demands things from Akane, such as instructing him to recapture Mirai after her escape.

Number 1's Powers
Kako governs the past as the first of the three Clock Keepers. Like the other Clock Keepers, a clock face appears above or below the target of Kako's powers when he turns their time backwards. Unlike Mirai, Kako does not need to directly move the hands on these clock faces to manipulate time; for example, Kako is able to turn Kou's time back just by touching him on the head.

Kako is able to turn back time on both small and large scales, reversing the entire school's time by almost an entire day. This suggests that Kako may be the most powerful among the three Clock Keepers, since both Akane and Mirai are only shown manipulating time on a much smaller scale.

When Kako turns back time for an individual, the effect seems directly opposite to Mirai's powers and the individual retains their memories.

On the other hand, Kako can also turn back time for the entire school, including all the people and objects within it. This reverses both the regular passage of time as well as changes caused by both Mirai and other supernaturals. As a result, the events that occurred during this time period are erased from almost everyone's memories, with the exceptions of supernaturals and humans with extremely high spiritual power. Interestingly, though Mirai's powers do not fully work on Kou due to his exorcist lineage, Kako says that Kou's memories would also be erased by the time reversal, which is only prevented by Akane using his powers on Kou. In addition, even after Kako reversed time, Nene still seems to remember the day's events until the point where she was knocked unconscious, although she is not a supernatural or a human with high spiritual power (like Akane and Teru respectively).

Presumably, Kako's powers also only work within the school, like Akane's.

Trivia

 * "Kako" is pronounced identically to "past" (過去) in Japanese, and is written either in kanji or katakana (カコ) during his various mentions/appearances.
 * When Kou asked him if he was called "Kako" because he can turn back time, he said that a name doesn't matter much to supernaturals