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Shuichi Kagaya (加賀谷 修一, Kagaya Shūichi) is the male protagonist of Gleipnir series. He has the ability to transform into a mascot looking dog and is helping Clair Aoki find her sister and her parents murderers.


Anime design

Shuichi is a slender young boy of average height with short black-brown hair and sometimes wears glasses. Following his encounter with Elena he has a scar across his neck.

While in his monster form, he transforms into a dog mascot costume with light brown hair color and top right face being darker brown. He has a gun and zip on his back, which can be opened and a person can enter and take control of him.


At the beginning of the story, Shuichi is kind and shy both inside and outside of school, and known to be quite intelligent as he got a recommendation for university and is often asked for help by his peers.

After learning of his ability to transform into a monster he was conflicted and incredibly frightened of his new reality, and soon felt detached from life, trying to cling to a sense of normalcy with cynicism.

Upon meeting Claire he felt terrified of the lengths she was willing to go in her quest to learn more about the monsters along her capacity to murder with seemingly any lack of restraint much in contrast to his still latent sense of humanity. After revealing how terrified he was of turning into a monster, Claire begun to care much more for him, a feeling that was mutual after he understood her motivations, being supportive enough to muster the willpower to stop her from committing suicide as she had promised to do, thinking he was dead.

As disclosed by the Alien, Shuichi's monster form reflects his inner desires and how he is empty in the inside in order for someone else to "fill him" and make up for his own weaknesses, a key part in Shuichi's codependent relationship with Claire. As the story progresses, he becomes much colder, more serious and outgoing, accepting his ability and trying to understand and improve it. While he maintains his kindness and altruism, he steadily begins to forget his own well-being and self-worth, adopting a self-sacrificial mindset.


Shuichi was speaking with the principal, turning down the principal recommendation. He was living a normal school life. Later Mifune came to him to tell him that she was chosen to receive the principal recommendation. She realized Shuichi had turned the offer, but he told Mifune that she earned it herself. Later while playing on his phone, due to his great smell, he smelled a fire and went to see. As he smelled a girl inside, he thought it won't have enough time to call for help, so he transformed into a dog mascot. He entered the building and broke the wall to save the girl and left her on the ground.

On the next day, he realized he lost his phone and arriving at school he smelled the girl he saved, who was holding his phone. She saw him transforming into a monster and wanted to speak with him. At the school roof, he tried to deny he was a monster, but the girl, Clair, pushed him down from the roof. While falling he transformed and then jumped back on the roof. She then started questioning him about what he was threatening she will reveal his secret. But Shuichi had no idea, and told her, he just transformed one day. On the way to her home, she introduced herself and showed him a coin she found, but Shuichi didn't know anything about it. In her apartment, she explained she was looking for her sister, who was a monster like him.

Power & Abilities

Shuichi monster form

When transformed he gains super human physical abilities: Greater strength, greater agility, greater endurance, a very good sense of smell (even stronger than a dog's). Also, some of his power works as well in his human form but the quality of the abilities is weaker. Shuichi might gain some sort of immortality when transformed as when his head was ripped off his 'neck' he was still alive while transformed but as the alien told him that it was a good choice not to transform back to his human appearance as he would have died on the spot.

From what is known for the moment his abilities are to sustain a "host" when transformed, furthermore increasing his abilities further but, the one that is inside can also control him to some extent depending on the person or the "compatibility" of the pair. The more aligned Shuichi and his partner are in their goals, the more powerful the monster form becomes, becoming more resistant to physical attacks (including intense fire breath) and gaining greater speed and reaction times. This "alignment" has the potential to use the other ability described below, in which the pair becomes a single, more powerful being. The host is also protected to some extent from attacks but when the attack is too strong then the host might suffer some damage, also Shuichi still feels pain in this form, it might be reduced to some extend ( seems that inside of the suit is very hot and has some slimy property in it ).

When he transforms he appears to gain some sort of gun, a revolver that seems to appear only when he is transformed and disappears when he goes back to his human form. The revolver might hold about 6 bullets in total, without more spare bullets and having a strength similar or even greater to that of an anti-material rifle, being able to incapacitate an angered Elena with two shots (one in the leg and one near the shoulder). It's assumed that the weapon could theoretically be used by anyone; though the weapon would be extremely unwieldy due to its size (as it is scaled to Shuichi's monster form), and the implied recoil would probably destroy the spine of a normal human if they attempted to use it.

Another ability that Shuichi owns that is discovered sometime later, only works if it meets some requirements. The requirements is that the host inside almost dies and if Shuichi doesn't want them to die the ability activates with Shuichi's intense will/feeling to save the person. This ability lets both of them become "one", as it says they literally become a single being that is much stronger and also looks different retaining similarities to both of them, first the appearance of the body of the host and second a beast-like appearance of the original body. As both become 'one' they end up sharing their memories, or at least the one that was inside Shuichi gains his memory's as he at first seems not being able to remember what happened though this is not true for other times the ability is used. In Yoshioka's case the previously mentioned gun changed from being a revolver to 2 smaller pistols and in Claire's case it changed into a katana. When this ability was first used with Elena, the transformation was strong enough to stop Kaito's regeneration and could kill him if Shuichi hadn't hesitated. Yoshioka describes this ability as being incredible and unique, and was the only way to defeat Honoka.


Clair Aoki

Elena Aoki


Nana Mifune


Tadanori Sanbe

Chihiro Yoshioka

Isao Kasuga

Yota Murakami

Sayaka Koyanagi


Miku Aihara






  • After Elena, Clair was the 2nd person to enter him with Yoshioka being the 3rd.
  • In Norse mythology, Gleipnir are the unbreakable chains that keep the wolf Fenrir until the beginning of Ragnarök, where the latter devours Odin.