"Troubled over his months-long stay at the hospital after his heart almost gave out and trying to adjust to his new surroundings, he is trying hard to find his place in the world. After being thrown into a new beginning, the chaotic circumstances have forced Hisao to rethink his apathetic disposition, especially regarding things like life, friendship, and his own future."
— Official Description

Hisao Nakai (中井久夫, Nakai Hisao) is the protagonist of Katawa Shoujo. He is an 18 year old male individual that has been diagnosed with cardiac arrhythmia and congenital heart muscle deficiency. The entire story is told from his perspective, starting with his heart attack from being confessed to by Iwanako at the beginning. Depending on the player's choices, Hisao can either end up in a relationship with one of the five main female characters or no one at all.



After many months of staying in the Hospital, Hisao becomes very detached and cynical, troubled at the fact of the life he once knew coming to an end and immediately being given a new one. Hisao is overall a good, kind-hearted person, even if at times, his good intentions can get him into trouble (such as during Hanako Ikezawa’s route, and at some points during Rin Tezuka's route as well). Other times he can have a severe tendency to have moments that border on the extreme (his arguments with Rin and Emi Ibarazaki immediately come to mind). He has trouble adjusting to his more physically disabled classmates, and has even found himself staring at other students on occasion (despite the fact that he mentally chastised himself for it), though as he spends time in Yamaku he grows accustomed to it little by little.

Hisao is not particularly strong-willed, but not necessarily weak either. For the most part, he gravitates towards strong people (the only exception to this rule was Hanako, who he wanted to protect; but even then, he was very reliant on Lilly Satou for a while), but he also needs a sense of stability, or at least a very clear direction as of where he's going.

Hisao is very skilled at Science, and also enjoys reading (partially because that was all he could do while he was flat on his back in the hospital). This becomes most apparent when Mutou suggests that he and Hisao form a science club in Emi's route. He's very much a 'math brain', and has trouble grasping things that are extremely abstract and 'illogical' in nature, hence his relationship with Rin during her path. He has problems with Social Studies, as shown in Hanako's route, and English in Lilly's route. In Shizune Hakamichi's path, it hints that it's likely that he has a desire to work at Yamaku Academy as a science teacher once he graduates from University.


Very little is known about Hisao's life before transferring to Yamaku Academy. He went to a standard Japanese public school, and often would fend for himself at home for things like meals, since his parents both worked long hours. He notably had three close friends by the names of Mai, Takumi and Shin. Oftentimes, after school, Hisao and his three friends would hang out at a local arcade. Of the four, Mai was considered the best at playing the games, and would always win against the other three, including Hisao. Hisao also would often find himself breaking up fights between Shin and Mai when they would argue over the outcome of the games.

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