The Seventh Mystery: "Hanako-san of the Toilet." First person: I (casual/masculine) Second person: you / (name) / (name)-chan Called by other Mysteries: No. 7 Tone: "...right?" "...is it?" "...you know." Characteristics: Usually innocent and playful, but his tone becomes cold and harsh when he gets angry or serious. He is effectively the leader of the Seven Mysteries. Akane Aoi sometimes calls him a "vile perverted brat."

The Sixth Mystery: "The Reaper." First person: I (soft/polite) Second person: you / (name) Called by other Mysteries: No. 6 Tone: Regional drawl (Kansai-style) Characteristics: Can drain the life force of anything he touches. He is selfless and detached, making it hard to tell what he's thinking at times.

The Fifth Mystery: "The 4 PM Bookstacks." First person: I (rough/casual) Second person: you (blunt) / (name) Called by other Mysteries: No. 5 Called by Hanako-kun: Tsuchigomori Tone: "...I told you," "...What?" "...it is." Characteristics: Sometimes takes a mocking or arrogant attitude. As the curator of the 4 PM Bookstacks, he can manage and view books containing the "past," "present," and "future" of everyone enrolled in the school. However, he cannot change the future.

The Fourth Mystery: "Shijima-san of the Art Room." First person: I (polite/formal) Second person: you (formal) / (name)-san Called by other Mysteries: No. 4 Tone: Very polite and calm, often drawing out the ends of her sentences. However, when she gets emotional, she stops elongating her words. Characteristics: Skilled at drawing; she can bring the things she paints to life.

The Third Mystery: "The Hell of Mirrors." First person: I (soft/polite) Second person: you / (name)-chan / (name)-kun Called by other Mysteries: No. 3 Tone: "...you know?" "...actually?" "...is it?" Characteristics: Constantly appeals to his own cuteness. He makes slightly thorny remarks or insults toward others. A bit of a tsundere? He can move through mirrors and look into the past.

The Second Mystery: "The Misaki Stairs." First person: I (polite/feminine) Second person: you (blunt) / (name) Called by other Mysteries: No. 2 Tone: "...right?" "...is it?" "...you know!" Characteristics: While she acts strong and a bit arrogant, she is caring and uses very human-like phrasing. She can transform between a human form and a fox form.

One of the First Mystery: "The Three Clock Keepers." First person: I (soft/polite) Second person: you / you (blunt) / (name)-san Called by other Mysteries: No. 1 Tone: "...right?" "...what?" "...it's like that." Characteristics: Usually maintains a polite, kind, honor-student tone with everyone, but when speaking to the Seven Mysteries, his polite speech is laced with thorns and provocations. He is a human who hates supernaturals, but by using a pocket watch, he becomes a half-supernatural governing the "present," gaining the power to stop time for 5 minutes up to 3 times a day, along with supernatural-level defense.