Yoshiharu Hisomu

Yoshiharu Hisomu is a main character and one of the group of seven kiznaivers in the titular anime, manga and novel series. His identification when he experiences pain is D-7.

He resembles the sin of Lust. His modern-day sin is 'The Immoral' (Japanese: インモラル, Romanized: Inmoraru).

Appearance
Hisomu is a naturally handsome, yet unkempt, teenager with mid-length, choppy purple taupe hair that has grey highlights, golden olive eyes, he has multiple piercings on both ears and a single labret piercing beneath his lower lip and he is perpetually seen with bandages covering his neck and his wrists.

His clothes always look quite worn down and tattered, and are invariably paired with flip flops. He appears to stand around 180 cm (5 feet, 10 inches) tall.

Several characters point out that Hisomu is a "natural hot guy" (in constrast with Tsuguhito Yuta, who had to work hard to achieve and maintain his current appearance). Despite his ratty look and lack of concern for personal care, he is often checked out when he is walking in the street, or on the rare occasions that he comes to class.

Personality
Hisomu was portrayed as an eccentric masochist throughout the entire series. As a masochist, he experienced arousal when experiencing, or even thinking about pain, and typically expressed this arousal quite vocally and without shame. This caused much chagrin among the kiznaivers, especially Yuta who was deeply peeved and put off by the unsuitable behavior. On top of that it is very ironic, since Hisomu was wired to enjoy an experiment that most people would find difficult to endure.

There is subtle implication that he was suicidal, though like the rest of his traits, he likely did not view it as a problem to concern himself with.

When he was in the same vicinity as Nico Niiyama he would occasionally act childish, as their respective outlandish personalities seemed to amplify each other's. He states to Hajime Tenga that he cannot swim and that he doesn't wish to drown, which contrasts his usual all-inclusive attitude towards pain and suggests that drowning is one of the few forms of pain he doesn't wish to endure. It is unclear whether he has a trauma related to this or anything else, because he seems to have decidedly pushed everything except pain out of his mind.

Aside from this, not much is known about him in general, and he is considered an enigma by everyone, even the former Kizna Committee members who watched his every move. Although he seems benign and spends most of his time smiling innocently, he is capable at all times of being blunt or ruthless with his words, which unnerves the other kiznaivers of his group.

Plot
Hisomu enters the series in episode 3, when he is forced out of hiding after evading everyone else for a while. When the kiznaivers find him, he is revealed not only to be a seventh kiznaiver chosen by Noriko, but one who enjoys pain.

After he joins the group in episode 4, thanks solely to Katsuhira Agata's impression upon him, he shows a very apparent interest in Katsuhira. Due to Katsuhira's high tolerance and lack of care about being subjected to pain, Hisomu focuses on him and gives him a sly and conspiring look, which causes his interested behavior to be interpreted by Hajime Tenga and others as a pick-up.

He clarifies to them that he is someone who only cares about feeling pain with no psychological attachments to the desire. He goes on to effectively play the role of a wildcard throughout the series, and his intentions toward the others in the kiznaiver group are constantly unpredictable.

However, in the end, he doesn't seem to be as averse to the idea of friendship as he was in the beginning of the series. This is likely due to the unwitting influence of Katsuhira, the only character in the series who has a definitive major impact upon his character.

Abilities

 * High Pain Endurance: It seems that Hisomu is able to withstand and enjoy physical pain, comparable to Katsuhira's high pain tolerance, with the contrast that the latter is not able to feel physical pain at all and that Hisomu feels pain every bit. In fact, in episode 9, it is shown that Hisomu was the only member of the group (save for Katsuhira) who was able to talk after they were able to hear each other's thoughts.
 * Intelligence: Similarly to Tenga, Hisomu is able to deduce answers from situations and come to valid conclusions easily. He is also able to understand new developments quickly, though he doesn't always like them.

Katsuhira Agata
One of the kiznaivers Hisomu is bound to by wounds. Hisomu takes a liking to and an interest in Katsuhira the moment their eyes meet in episode 3, taken by Katsuhira's uniqueness with regards to pain. Hisomu, along with Nico, later support him when times get tough within the kiznaiver group, and Hisomu serves as his confidant when the two begin living under the same roof.

They are shown to be on friendly terms with each other throughout the entire series.

Nico Niiyama
One of the Kiznaivers he is bound to by wounds. These two are on friendly terms. Even though in episode 3 Nico calls Hisomu a "scallywag" and later attempts to compete with his "weirdness," she appears to still want to befriend him. Nico and Hisomu are the first of the group to establish with Katsuhira that they still want to be friends even after the conclusion of the kiznaiver missions in the summer.

At the end of the series, Hisomu is shown hanging out with her separately from everyone else and upon observing her attitude towards her friends, notes that Nico is actually pretty mature.

Noriko Sonozaki
Noriko was the ringleader of the now-concluded Kizna Experiment. In contrast with the rest of the Kiznaivers, Hisomu doesn't necessarily seem to dislike Noriko at all. In fact, he seems to view her somewhat positively, as she is the one responsible for choosing him to partake in the experiment, thus providing him with more "stimulation." He can be blunt with her but is generally polite, just as he is with everyone else.

Tsuguhito Yuta
One of the Kiznaivers he is bound to by wounds. He behaved very childishly with Yuta and often sits very close to him, which seemed to bother Yuta immensely due to how weird and "gross" Yuta views him to be. Yuta expressed personal disapproval of him in episode 8, when he hurt Maki for the sake of his own gain, to which Hisomu didn't seem to pay any mind. The two didn't seem to grow any closer by the series' end.

Honoka Maki
One of the kiznaivers he is bound to by wounds. He doesn't say much to Maki throughout the series but he closely observes her situation until finally, he arbitrarily takes the opportunity to hurt her heart during the storm by twisting the current situation around and stating, in response to Maki's interrogation of his "messed up" character, that she is the only one who hangs out with the kiznaivers to make herself feel better and rid herself of the guilt surrounding her past. Honoka feels immense guilt and shame at the accusation and runs off, while Hisomu remains where he is and expresses pleasure at feeling the hurt he inflicted.

Hajime Tenga and Chidori Takashiro
These two are kiznaivers he is bound to by wounds. Though he seems slightly closer with Tenga, he generally behaves very neutrally towards the both of them, likely due in part to his knowledge of their (in his eyes) unappealing and messy love life. However, there is no doubt that all of them are friends at the end of the day.

Quotes

 * "I personally don't believe connections are made so easily." (Episode 3)
 * "Could you die right now for me?" (to Katsuhira Agata, episode 3)
 * "If you don't know what state your wounds are in, of where you're hurting... If you don't know that for yourself, there's no point in trying to share it with others, is there?" (Episode 12)

Trivia

 * The name Yoshiharu means "good luck" (吉), "righteous" (義), "good, virtuous, respectable" (良), "fragrant, virtuous, beautiful" (芳), "reason, case" (由) or "joy, pleased" (悦) (yoshi) and "light, sun, male" (陽), "spring" (春) or "clear weather" (晴) (haru).
 * Yoshiharu's surname Hisomu means "sun, day" (日) (hi) and "dye" (染) (somu).
 * Hisomu doesn't know how to swim.
 * Hisomu is the only kiznaiver to not fall in love with someone and he displays no apparent romantic interest at any point toward any character in the series.
 * In Episode 4, Hisomu appears to enjoy sweet things, briefly mentioning that he prefers Lumonde Bourbon over Baum Rolls.
 * He also asks for caramel ribbon ice cream when he, Hajime Tenga and Tsuguhito Yuta try to order from an ice cream counter.