Souta Hori, the younger brother of Kyouko Hori and son of Kyousuke and Yuriko Hori, grows accustomed to his parents' frequent absences due to demanding work. This necessitates Kyouko managing the household, inadvertently fostering Souta's early independence. Despite this maturity, he exhibits typical childhood habits like discarding clothes in the living room to rush out and play. Souta possesses fair skin, messy gray hair inherited from his father, and olive-colored eyes, giving him a resemblance to Kyouko. After a timeskip, he matures into a tall, slender teenager who closely mirrors Kyousuke, often seen in a school uniform of white shirt, blazer, dark pants, and a necktie gifted by Izumi Miyamura. Personality-wise, Souta is obedient, levelheaded, and kind. He shares a close bond with his sister Kyouko and develops a deep fondness for Miyamura, whom he respects as an older brother and affectionately calls "big brother." Souta demonstrates perceptiveness beyond his years, recognizing Kyouko and Miyamura's mutual feelings before they do. He intentionally stays outside after school to give them alone time, though they misinterpret this as early rebelliousness. His emotions are uncomplicated: he beams with happiness seeing Kyouko and Miyamura wear rings, interpreting it as marriage, yet cries easily over minor incidents, earning him the label "crybaby" from Yuuna Okuyama. His interests include the anime "Hurricane Star," which he frequently watches or sings songs from, inadvertently causing Kyouko to memorize the lyrics. Souta's narrative role begins when he trips and sustains a nosebleed after being startled by a dog. Miyamura assists him and escorts him home, facilitating the first meeting between Miyamura and Kyouko and establishing Souta as their initial connection. He repeatedly asks Kyouko to invite Miyamura back, providing her excuses to spend time with him. Later, an innocent remark to Kyouko about seeing Miyamura with another girl inadvertently creates tension due to misunderstanding. Souta harbors a dislike for carrots and complains when they are added to curry. Post-timeskip, he maintains his closeness with Miyamura while navigating adolescence, retaining his core traits of kindness and perceptiveness.