Katsuhira Agata

Katsuhira Agata (阿形・勝平) is the main protagonist of Kiznaiver. His moods barely fluctuate, and he pays little attention to other people. He is constantly bullied, but he doesn't feel pain and is therefore not scared of people hurting him. His sin is "Gudon" (The Imbecile).

Appearance
Katsuhira is a tall, slim young man with droopy, grey eyes and often an emotionless expression on his face. He has short curly white hair with brown highlights in a shaggy pixie cut. He is usually seen wearing his uniform school consist white shirt with black accents on the cuffs and collar, accessorized by a blue tie with a black cross. He appears to be around 176 cm.

Personality
Katsuhira is rather indifferent in all situations, whether he feels pain or joy. He is shown to be emotionless and is also shown to be oblivious to the feelings of other people despite wanting to build bonds. Due to his lack of interest in himself and others around him, he has trouble forming connections. However, it seems like his lack of interest started in grade school as Chidori's confession stated that she wishes he would go back to being his fun and caring self.

Katsuhira, despite having little emotion, does care for those around him, even to the point where he is willing to risk his own safety for the other Kiznaivers, including jumping off a bridge early in the series to prevent Tenga from doing the same thing.

Abilities
While technically a disability, Katsuhira does not feel pain. This means when the other Kiznaivers are affected by someone else's or their own pain, Katsuhira is not inhibited at all. Although he still takes damage when his own body is injured.

Relationships
Noriko Sonozaki

Though Katsuhira claimed that he did not know Sonozaki, it is heavily hinted that Katsuhira has a past with Sonozaki and that he forgot about. Of all the Kiznaivers, Katsuhira seems to have the best relationship with her. In the beginning, Katsuhira's heart starts to race when Sonozaki got really close to him. She takes note of this and asks him why, and he responds that he has never been that close to a person unless they were beating him up. Given that Katsuhira is void of most emotion, this is a big indication that he has interest in her. Also, rather than call her Sonozaki like the rest of the Kiznaivers, he calls her Nori-chan, causing Chidori to get jealous. He is also the one that Sonozaki calls when she wants something from the Kiznaivers. In Episode 6, Katsuhira finds Sonozaki and expresses his disappointment in her, which is the most candid thing he has ever said to anyone. As well as him being extremly truthful towards her, it seems as if he thinks very highly of her which is why he was disappointed with her actions. Katsuhira also seems to be able to find his true self whenever he is with her, as it seems that she has the key to his past.

Chidori Takashiro

Chidori and Katsuhira have been friends for a long time, even before Katsuhira became indifferent to life. Chidori calls him "Kacchon", which shows affection while Katsuhira calls her "Chidori" without any honorifics, showing that he at least feels somewhat comfortable with her. She is shown to care a great deal for him by cleaning his house with him, being concerned about his bullying issues even to the point of getting upset when he says it doesn't matter, getting jealous when he chooses to talk to Sonozaki rather than leaving with Chidori and the rest of the gang, and risking her life by jumping off of a building onto an unstable lift where Katsuhira is to save him. Prior to his personality change, Chidori confesses that she was in love with him, however, it is unclear whether or not she still feels this way. It is hinted that she does when she blushes around Katsuhira and gets jealous of Sonozaki. During his introduction when he states that he feels indifferent towards people and doesn't care about how they feel, Chidori gets extremely irritated and points out how he used to be funny and nice and is driven to the point of tears as she explains how she's been trying to get him back to the way he was previously. Katsuhira shows a fairly decent amount of emotion (for him) after seeing her in her state and revises his introduction, saying how he is happy that Chidori was in love with him, despite it being past tense. After they fall off of the building, he asks if she is alright, showing that he does care about her as a friend.

Hajime Tenga

Tenga is the one who saves Katsuhira from bullies during the first time they meet. He is shown to care about Katsuhira when he follows him home and decides to live with him, claiming that he promised to protect him. Although, he may be working in his own self-interest because he has to feel any pain Katsuhira's body experiences as well. In order to prevent Tenga from jumping off a bridge later, Katsuhira himself jumps, even though his body would still be affected from the fall. He and Chidori are the only Kiznaivers to run to his aid, while the others go to check on or prevent Yoshiharu from escaping.

Hisomu Yoshiharu

When Hisomu is first mentioned, in Episode 3, Katsuhira states how he feels sorry for Hisomu and starts feeling the want of having a connection with another person. Katsuhira soon realizes while the Kiznaivers are chasing Hisomu that he probably wont talk to the Kiznaiver unless only one person like himself went to him, because Hisomu made direct eye contact with him in the supermarket. Katsuhira goes to meet with Hisomu and Hisomu asked if he could die for him at that moment, and Katsuhira shows no resistance to Hisomu. Later in that scene Katsuhira causes Hisomu to bliss out after jumping off a bridge into oncoming traffic. In Episode 4 Hisomu claims that he is despicably glad to meet Katsuhira after he said to all the other Kiznaivers that it was nice to meet them. Later in Episode 5 it is shown that Hisomu was trying to hurt Katsuhira purposely after asking him if he could hold the firewood he was chopping or if he could sit underneath it.

Nico Niyama

These two seem to have a budding friendship. In Episode 4 Nico gives Katsuhira the green peas she doesn't like. And in Episode 5 she protests to the fact of Katsuhira getting hurt by Hisomu.