Taiyō Mitsuboshi

Birthday: October 4, Blood Type: O, Height: 175 cm

A young man who worked at Satou's part-time job, "Princess Imperial." His family includes his mother (voiced by Mai Nakahara). He had feelings for Satou and confessed to her, but was rejected. This was discovered by the store manager, who then confined him. Although Satou rescued him, he developed a fear of adult women. As a result, when he accidentally found a flyer searching for Shio, he began to seek salvation in her. Upon meeting Shio, his feelings were confirmed.

His feelings for Shio are that she is an "angel who purified him," making him feel as though he was becoming clean from the corruption caused by adult women. However, his behavior became increasingly abnormal, such as smelling the search flyer for Shio, bringing several copies of the flyer into his room, and getting upset if they were stepped on, to the point where even Shouko was repulsed. His condition worsened as the story progressed, and he would cling to Shio's search flyer whenever his trauma was triggered by other adult women. He even exhibited behavior suggesting he wanted to possess Shio, thinking, "Only I can be Shio's knight." When he learned that Asahi was trying to reclaim Shio, he tried to take her back from him and even insulted him. He once tried to stop Shouko from going to Satou's house, but his true motive was to prevent more people (whom he called "hindrances") from being captivated by Shio. Despite this, he showed a reasonable side and genuinely wanted to return to being a normal person.

He is one of the few people who knows that Satou is with Shio and has actually witnessed Satou taking Shio away. Satou saw through his attraction to Shio and used it to make him cooperate in keeping Asahi away, on the condition that he could meet Shio. Initially, he refused to cooperate, but when Satou gave him Shio's socks, he quickly gave in. Although Asahi became suspicious of him, he successfully kept Asahi away. However, the promise to meet Shio was broken, and Asahi, who had returned, threatened him to get Satou's address. He confronted Asahi, demanding the return of Shio's tie and insulting him, which led to Asahi hitting him with a metal bat. Terrified, he fled and later visited Satou's apartment, seeking salvation from Shio. One day, he mistakenly thought Shio was in "Room 305" of Satou's apartment and encountered Satou's aunt, who confined him. He managed to escape and encountered Shio.

He sought Shio's help to purify his corrupted self, but she rejected him, saying, "I'm not clean at all." In a state of emptiness, he was found and taken in by Satou's aunt. After the incident, he mentally collapsed, keeping Shio's search flyer in his pocket.

In the anime version, he also seeks help but is left behind without any direct conversation. After the incident, he mistakenly believes that Shio died with Satou and withdraws into his room in a daze.