No.1 The Clock Keepers

Current Representative of the Mystery

「三人の時計守」
The three clock keepers are the first of the Seven Mysteries. It is the fourth school mystery to be introduced in the series. They are the first school mystery to be seen independently outside of their boundary and unrelated to their rumor.

Unlike the other school mysteries, the clock keepers consist of three members — Kako, Mirai and Akane. They represent past, present and future. Akane was tricked into forming a contract with the clock keepers after falling for a scheme they orchestrated. He is now currently in a 6-year-long contract with them, until his graduation.

The clock keepers are able to control time. Kako and Mirai have the ability to turn back and move time forward respectively. As a contractor, Akane can stop time for five minutes up to three times a day. He notes that if he goes an entire school day without any incidents, he is able to use it for fifteen minutes at a time.

Boundary
The boundary of School Mystery Number 1 is unknown, so is their Yorishiro.

It is noted Hanako does not know where their boundary is located at due to a bad first impression. He had said the Clock Keepers "can do all the pervy stuff [they] want" with their powers, causing the keepers to "never want to see him again" and refuse to tell him where their boundary was.

In Chapter 103, Natsuhiko claims that the location of School Mystery Number 1's boundary has been found, thanks to having planted the tsueshiro on Akane earlier. In the following chapter, Natsuhiko himself goes to the mechanical room of the Big Clock of The Sealed Auditorium, and spills his blood, which later coats and covers the entire mechanical workings. All the while, Natsuhiko claimed in the form of a rumor that his blood can instantly destroy any supernatural. Thus, it implies that the Clock Keeper's Boundary, or its entrance has something to do with the Big Clock at The Sealed Auditorium that they control in the first place.

The Rumor
Numer 1 Strażnicy Zegara