Sōta Hori is the younger brother of Kyōko Hori and son of Kyōsuke and Yuriko Hori. He resides with his mother and sister, his parents often absent due to work, fostering self-reliance alongside typical childish habits like scattering clothes in the living room, blending independence with moments of immaturity. He has fair skin, messy light gray hair, and olive eyes. As a child, he resembles Kyōko. After a significant time skip, he matures into a tall, slender teenager who closely mirrors his father. His post-timeskip appearance features a high school uniform of a white shirt, blazer, dark pants, and a necktie gifted by Izumi Miyamura, whom he affectionately calls "big brother." He also wears another school uniform with a sweater layered over a white shirt. Sōta exhibits obedience, perceptiveness, and emotional vulnerability. Hard-working, kind, and helpful like his mother, he forms a close bond with Kyōko, relying on her as a maternal figure. He communicates straightforwardly, unembarrassed by sensitive topics, and displays sharp perceptiveness—recognizing Kyōko and Miyamura’s mutual romantic feelings before they acknowledge them. To facilitate their alone time, he deliberately stays outside after school, misinterpreted by Kyōko and Miyamura as early rebelliousness. Classmate Yuuna Okuyama describes him as a crybaby, prone to tearing up over minor incidents. He enjoys anime, particularly "Hurricane Star," often singing its songs at home and inadvertently causing Kyōko to memorize lyrics she finds embarrassing. He dislikes carrots and complains when they appear in dishes like curry. His role begins when he trips and gets a nosebleed after a dog startles him. Miyamura helps him home, leading to Miyamura’s first encounter with Kyōko and initiating their central relationship. Sōta becomes deeply attached to Miyamura, viewing him as an older brother and frequently asking Kyōko to invite him over. He serves as a recurring excuse for Kyōko to spend time with Miyamura. He expresses visible happiness upon seeing Kyōko and Miyamura wearing rings, interpreting it as a sign of impending marriage. Within his family, Sōta shares a typical sibling dynamic with Kyōko—mutually affectionate yet occasionally bickering. He seeks her guidance and fears losing her. His communication with father Kyōsuke is blunt, mirroring Kyōko’s manner, and Kyōsuke believes Sōta resembles him physically. Interactions with mother Yuriko are infrequent but reflect an average mother-son relationship. Beyond family, his friendship with Miyamura is significant; he trusts him implicitly, believing even far-fetched statements, and consistently seeks his company. With classmate Yuuna Okuyama, he initially faces bullying for being a "crybaby" and overly attached to Kyōko. Their relationship evolves into friendship, with Yuuna occasionally visiting to play. Post-timeskip, they develop romantic feelings. Sōta confesses having loved Yuuna for as long as he can remember, resolving her initial misunderstanding. Sōta develops from a dependent child to a more independent teenager. His perceptiveness and emotional intelligence remain consistent, particularly in supporting Kyōko and Miyamura’s relationship. The time skip highlights his physical maturation and deepening bond with Yuuna, illustrating his growth into adolescence.