A parallel dimension that can be accessed through portals by certain people. With its heavy atmosphere, it is a place housed by Nullities.

The various pocket dimensions that are part of Mu. While Mu is the parallel world, Fragments can be described as individual "dungeons" of that world that may or may not connect to one another.

High-tech dome shaped convention center that is a pinnacle of Shiroki City's technological inventions. The biggest concerts are held here, and a part of it contains a museum that gets used for special educational tours.

Location of Volume 3's climax.

Location of the school trip in volume 2. A mountain region surrounded by a lush forest. Travelers often stop by to indulge in its various shops, visit its shrines, or relax in one of the many hot springs in the inns.

Shadowy creatures that take various forms and reside in Mu's Fragments. Said to be manifestations of human emotion.

An empowered person who has gained access to Mu and can manifest a spirit weapon known as an Armament.

Spirit weapons that can be summoned by Awakeners. All of them come with a unique combat ability connected with its wielder's inner desires.

(CV: Kouki Uchiyama)

Protagonist of the story. Reserved yet curious, he was saved from death and revived as an Awakener. He wields a shield Armament with the ability Assimilator's Core, allowing his shield to transform and take on the properties of another Armament.

(CV: Yui Horie)

A beautiful transfer student who joined Kazuki's class. A Nullity hunter, she took up that mantle in order to avenge her brother's death at the hands of the shadowy creatures. Despite appearing cold and distant, she eventually warmed up to Kazuki and his group of friends. Wields a sword Armament with the ability Crimson Lust.

(CV: Kana Hanazawa)

The first of Kazuki's childhood friends and a member of the school's swimming club with a special affinity for the spiritual. Polite, gentle, and caring, she occasionally shows a much more clingy and jealous side. After coming to terms with her feelings towards Kazuki and Sayaka, she unlocks her Armament, the bow with a powerful ability, Innocence Arc. 

(CV: Rie Takahashi)

An idol in hiatus. Often seen cheerful and upbeat as an idol, she hides a rather different personality and hidden frustrations behind that mask. Tends to show up in different hairstyles and hair colors, but her "ordinary civilian" look features a predominantly green side plait and glasses.

After unlocking her powers as an Awakener, she acquired the mic-shaped staff with the ability Prismatic Reverb.

(CV: Yoko Hikasa)

Voluptuous school counselor and an occasional substitute teacher. Lazy, haggard, and a tease, she nevertheless shows concern for her students. Quite knowledgeable with Mu and Nullities. She wields a necklace Armament with the ability Yata no Kagami.

(CV: Takahiro Sakurai)

An affable yet mysterious silver-haired man who works as a personal lawyer and legal adviser of the Ishida Conglomerate. Behind the scenes, he leads the group Euphoria, a minor organization that is heavily connected to Mu and Nullities. He seems to have some connections with people involved with Mu, having known Sayaka's brother as well as Miyuko Sadohara.

(CV: Kaori Ishihara)

Ace of the swimming club and Amagi's junior. Feisty and energetic, she brings about limitless energy. Very honest and encouraging of her friend's feelings. However, she can be overly positive and naive, bringing her at odds with others in terms of decision-making.

(CV: Yoshitsugu Matsuoka)

One of the two heirs to the Ishida Conglomerate. Reijy is always seen with his clique and exerts a strong influence over Fuyusato Academy. A sworn enemy of Kazuki, whom he sees as beneath him and a useless slacker. However, their rivalry goes a bit deeper than that.

(CV: Ayana Taketatsu)

Nosy and frank writer of Fuyusato's gossip mill. The aspirant reporter also doubles as a member of the school's student council. Close friends with Fujiwara, and loves to show affection by teasing and mischievously getting under the skin of people.

(CV: Sarah Emi Bridcutt)

Vice-president of Fuyusato's student council. A foreigner who is very straight-laced and plays by the rules. This largely puts her in conflict with the more lax students in the school, such as Rin Amamiya. Shows an interest in the arts.

(CV: Nao Touyama)

Glamorous with her bleached orange hair, polished nails, and earrings, she exudes a strong presence among the students. Also follows gyaru culture and social media fashion. Her free-spirited attitude largely puts her at odds with Bloomenfled, and her brash nature sends fear through troublemakers like Shiki.

Her uncle owns the hobby shop First Strike.

(CV: Yui Ogura)

Kazuki's little sister. Very responsible and doting. A big fan of idol culture and Yuki-tan. Despite her snarky attitude at times, she cares a lot for her older brother.

(CV: Rina Hidaka)

Hikari's friend and an exceedingly shy and soft-spoken girl. She was caught up in the Chronodome incident in Volume 3. After being saved in the said incident, she starts showing some affection towards Kazuki as her "older brother."