|Debut (Manga):||Chapter 1|
Genichirou Kosukegawa (Great Grandfather, Deceased)
Teruharu Kosukegawa (小介川 英生, Kosukegawa Teruharu) is one of the protagonists of the series.
Teruharu Kosukegawa is short for his age. He has short black hair that lays flat on his head, with a few stands sticking up in the air. He also has brown eyes.
Kosukegawa is a justice loving boy who is a huge Kamen Radier otaku (something that stems back all the way back to his childhood). His morals and beliefs come directly from the series.
Because of his beliefs of love, justice, and friendships he can come off as naive to others. Notably, those like Sora who believes in the exact opposite and find his ideals disgusting. One of his many beliefs, is that fighting should never be an answer. Which often results in him trying to stop a fight at the cost of injury or even his life. Some find this heroism foolish, while others are amazed and see it to be courageous. His nickname Hideo is a play on words, it meaning "Great Man". Although its ironic, since others consider him more of a "failed hero".
Kosukegawa is a non action guy, not knowing any martial arts or any use of weaponry, unlike his friends. Instead he will try to befriend that person. This usually has him gain more friends then enemies, which can be the greatest strength.
In contrast to this he can be very perverted, having many fantasies about Motoko. His perverted airs go unnoticed sometimes, but when noticed (usually by Motoko herself) many are freaked out.
Teruharu Kosukegawa as a child and still to this day is a huge fan of the Kamen Raider series. He met Kannami in elementary school and gave him insight about why he liked Kamen Raider series. Even though it is fictional Kouskegawa believed that it gave morals and beliefs that are true in real life. After this encounter they became best friends. In third grade Kannami had to move to America. Kousukegawa gave Kannami his favorite Kamen Raider action figure, so that he would never forget him and by missing the figure he won't forget Kannami.
His story with Motoko Gettou began with witnessing one of HiFuMi beat up a guy at a alley. Motoko begged Kosukegakwa not to tell anyone and offered him anything. The two became friends and he tries to confesss to her several times. He manages to befriend all of Motoko's personalites, who prefer for him and Motoko to get together, instead of Kannami.
When Hibiki kisses him and changes back to Motoko, an awkwardness surrounds him and Motoko, because Motoko is avoiding him. After confronting her Motoko apologizes to him, which confuses Kosukegawa, saying, "That's strange", hurt Motoko runs off.
Kosukegawa is the "bait" used in Kannami's and Jin Hayase's plan to cause HiFuMi to feel anger, to bring out Zero, the personality carrying Motoko's anger. To his surprise Ralph, a Radier fan he befriended on the train was part of the plot. The watch Ralph gave Kosukegawa was actually a tracking device. He calls Ralph out asking why he and his teammates are doing this and doesn't understand Ralph's explanation.With the help of needles to enhance his muscles and Kamen Radier cosplay he fights against Zero. He is able to go toe to toe with her, because he recognized Zero's fighting style. When the times comes Kosukegawa is unable to hit her in the neck to finish her, feeling he couldn't bear to hurt Motoko. This gives Zero the chance to pin him down and finish him. Kosukegawa in desperation yells, "I love everything about Motoko!", which has her stopped by, Motoko, Hibiki, Mikiri, and Fujiko. Motoko collapses apologizing to Kosukegawa and her face appears to be a combination of her and HiFuMi.
Him and Motoko eventually become boyfriend and girlfriend after Motoko overheard him pray for it at a temple for his New Year's prayer.
When Motoko's disappeard, he asked HiFuMi everyone day when she'll return, which annoyed and sadden Hibiki who doesn't know either. After finding a letter from HiFuMi that only explained that "they'll be gone for awhile" and questioning Kannami he goes on a journey to search for HiFuMi and Motoko.
Kosukegawa, along with Ginga and Hino trespass the Soe Clan's estate when they find out that HiFuMi resolve to bring back Motoko by fighting her father, Tatsuya Rukawa. Due to Botan's betrayal (as she believed that he should witness the fight) he is able to see HiFuMi and Tatsuya's battle. At the end of the battle Tatsuya throws Motoko at Kosukegawa asking him to take care of her. Motoko wakes up in his arms and the two share their first "real" kiss. Later, he notices that Motoko and HiFuMi are now one; seeing that Motoko has taken a few of their habits and memories.Years later he and Motoko are married. They have three daughters who look a lot like Hibiki, Fujiko, and Mikiri.
His relationship with Motoko was at first friends. Even though Motoko promised to give him anything he wanted if he keep her secret, Kosukegawa doesn't force her to do anything against her will because dictates it. (However, his morals don't stop Kosukegawka from having frequent fantasies about Motoko as his wife serving him wearing only an apron.) Sometimes his pervert atmosphere goes unnoticed by Motoko, but sometimes others would pick up on it and become very disturbed.
They offically became a couple around New Years' when Motoko overheard him wishing that they could be boyfriend and girlfriend. Depite dating for a year, Kosukegawka and Motoko still haven't kissed.(Hibiki kissed once Kosukegawka and switched to Motoko the last second to try to force them, but Motoko and Kosukegawa agreed it doesn't count.)
Kosukegawa has been able to gain the trust and friendship of all of Motoko's personalities (with the exception of Zero). Each of them would prefer that Motoko went out with Kosukegawa instead of Kannami. He regularly goes on "dates" with all of them them and it could said that he is dating four people instead of one (Motoko, Hibiki, Fujiko and Mikiri). Even so, he loves Motoko first and foremost and refuses to do anything with HiFuMi that he knows Motoko would disapprove of.
Hibiki is the first personality of HiFuMi that Kosukegawa met. Hibiki tends to flirt and tease the most with Kosukegawa out of all of the personalites, although over time, she becomes slightly more serious with him and deeply trusts him. One time, she asked if Kosukegawa didn't like her because he wouldn't kiss her. He replies that he loves Motoko first, to which she responded by kissing him and turning back to Motoko the last second with the hopes that he and Motoko would move up in their relationship.
At first, it would seem that Fujiko didn't like Kosukegawa, but that is proven untrue after they go on a date to get to know each other. Fujiko like all of the personalities are attached to Kosukegawa, as seen when she goes as far to threaten to kill someone threatening Kosukegawa's life.
Mikiri is the playful and childish personality of Motoko, so she loves to go out and play with Kosukegawa. She refers to him as Kosukegawa-niichan (Japanese for elder brother).
Kosukegawa doesn't like Zero and is fearful that she could be the true personality instead of Motoko. He once had a dream where he approached Motoko and saw her with the emotionless eyes of Zero.
From the interactions with his mother, it could be said that she misses when he was a young, and now that he is a teenage boy, he refuses to do things, such as holding hands with her or taking a bath together like they did when he was a child. Her interactions with Motoko, Ginga, and Hino could suggest that she actually wanted to have a daughter. His mother does care for him wanting to give him his grandfather's old clothes when Kosukegawa went on a journey to find Motoko.
On the other hand, Kosukegawa's Father spends most of his time on business trip, so Kosukegawa doesn't see him often. His father once thought that Kosukegawa obsession with Kamen Radier would mean that he had no interests in girls. This caused him to set a arranged marriage meeting with, ironically Kosukegawa's current girlfriend Motoko.
Kosukegawa is not a martial artist or strategist. This is noticable, since he tends to hang out with people who have martial backgrounds, such as Motoko, Hino, and Ginga.Kosukegawa has been shown to be extermely durable, which is played for laughs. An example would when he was hit by a upcoming log and was able to come back virtually unharmed.
However, in the Zero Arc, Kosukegawa was given enhancements to his muscles from Naada's needles. This gave him a significant increase in strength and gave him a bulkier build. Although, untrained he was able to hold his own aganist Zero, because he was able to recall that she had martial traits of all three of HiFuMi.