Souta Hori is the younger brother of Kyouko Hori and the son of Kyousuke Hori and Yuriko Hori. He resides with his mother and sister due to his parents' frequent work absences, which fostered a degree of independence alongside typical childish habits like leaving clothes scattered around the living room. His first meeting with Izumi Miyamura occurs when a dog startles him, causing him to trip; Miyamura then escorts him home. This event introduces Miyamura to Kyouko Hori's home life. Physically, Souta has fair skin, messy light gray hair, and olive-colored eyes, showing resemblances to both his sister and father. As a child, he stands about 110 cm tall. After a timeskip, he grows into a tall, slender teenager more closely resembling his father, frequently seen in school uniforms, one accessorized with a necktie gifted by Miyamura. Souta exhibits an obedient, kind, and perceptive personality. He forms a strong attachment to Miyamura, calling him "big brother," and actively facilitates interactions between Miyamura and Kyouko by inviting Miyamura over to watch anime or sing songs. He demonstrates emotional sensitivity, crying easily over minor incidents, and displays protectiveness toward his sister. He recognizes the mutual romantic feelings between Kyouko and Miyamura before they acknowledge it themselves, deliberately creating opportunities for them to spend time alone together—a behavior the couple mistakes for early rebelliousness. His role extends beyond family; he serves as Kyouko's recurring excuse to invite Miyamura to their home, reinforcing their evolving relationship. Post-timeskip, his continued admiration for Miyamura reflects their enduring bond. Souta dislikes carrots and often complains when they appear in dishes like curry. His birthday is October 18.