Raidō, whose given name is later revealed to be Shōta, is an ordinary high school boy beginning his first year of high school. He is tall, with short black hair and brown eyes, and he has a stern, stoic face that makes others perceive him as intimidating or even scary. His expression tends to stay fixed even when he is feeling strong emotions such as happiness, sadness, shock, or determination, and this stiffness has in the past kept other people at a distance from him. Because of that experience, he enters high school with a clear motivation: to have a fulfilling school life and to make one hundred friends.

Beneath his forbidding exterior, Raidō is earnest, gentle, and friendly once he gets to know someone. He is frank about his emotions and is not afraid to act when he believes something should be done, which is shown early on when he pushes his desk against his classmate Reina Aharen's desk after a day of closeness, an act that becomes the foundation of their friendship. His most distinctive inner trait is a wildly overactive imagination. Whenever Reina behaves in a way he cannot understand, his mind spins her small actions into elaborate, dramatic, and increasingly absurd explanations, and he sometimes acts on these imaginings before the real reason is revealed. He is aware of this habit and considers it a problem, but he reasons that preparing himself for all possibilities, however unlikely, helps him face anything.

His central motivation is connection. He wants friends, and he deliberately sets out to befriend Reina, who sits next to him in class and who had been avoided by her previous classmates for being clingy, awkward, and timid. Through their friendship, Raidō becomes her first real friend and the person who most fully accepts her as she is. He looks after her, quietly adapts to her unusual sense of personal space, and joins her in a wide range of activities, including sports, studying, dancing, and board games. As their bond deepens, he becomes her boyfriend and is openly affectionate, casually complimenting her appearance in a matter-of-fact way that often embarrasses her.

In the story, Raidō serves as the male protagonist and the patient, good-hearted partner who reaches out to Reina and helps her come out of her shell, even as he comes out of his own. His key relationships include Reina herself; Mitsuki Ōshiro, Reina's childhood friend, who initially regards Raidō as a scary person trying to trick her friend; and later friends such as Ishikawa, Hanako, and Riku, whom he earns over time. His decisive and protective side is evident when Mitsuki challenges him to a game of reversi with the condition that losing means cutting off contact with Reina, a stake that gives him the determination to overcome a losing position and win, after which the tension between them dissolves and they become friends.

Raidō's development is gradual but meaningful. He moves from awkwardness, confusion, and frequent misunderstandings toward a greater ability to read Reina, greater reliability, and growing confidence, culminating in a genuine and mutually supportive romantic relationship. He has no supernatural abilities; his notable traits are his calm but intimidating appearance, his loyalty and readiness to act, and his tendency to recast ordinary moments as grand fantasies, a quirk that defines much of his personality and drives the comedy around him.