Masayuki Hori is a third-year high school student at Roman Academy and serves as the president of the drama club. He stands at 164 centimeters tall, a height that has significantly shaped his role within the club. Hori is a naturally gifted actor and formerly performed in plays, but his short stature made him unsuitable for leading roles while his skill made him stand out too much for minor parts. As a result, he stepped away from the stage and now handles stage design, props, and overall production work instead. Outside the drama club, Hori also works as an assistant to Umetaro Nozaki, contributing detailed backgrounds for Nozaki's shōjo manga. His best academic subjects are mathematics and physics, and his personal hobbies include watching movies and plays as well as traveling.

Hori's personality is defined by a strong sense of responsibility and a strict but caring demeanor. He is highly organized and efficient, always ensuring that club activities run smoothly and that everyone fulfills their duties. This sense of duty is most visibly channeled toward Yuu Kashima, a fellow drama club member whose carefree and often troublemaking behavior frequently tries his patience. Hori has taken it upon himself to keep Kashima in line, resorting to aggressive physical methods to drag her back to practice or class. This dynamic has earned him the reputation of being Kashima's escort. Beneath his harsh exterior, Hori behaves like a doting caretaker toward her, and there are strong implications that he harbors romantic feelings for Kashima, although he vehemently denies this. His emotional restraint sometimes breaks in her presence, causing him to react in an unusually childish or flustered manner.

Hori's motivations center on maintaining order and responsibility within the drama club and, by extension, his school life. His strictness is not born from malice but from a genuine desire to see the club succeed and to look after its members, particularly Kashima. He is a reliable and trusted upperclassman who is well-liked by his juniors. Hori's character development is subtle; he gradually reveals a more vulnerable side through his interactions with Kashima and his growing comfort in assisting Nozaki. Notable abilities include his keen understanding of theatrical production, his practical skills in stagecraft and prop-making, and his talent for artistic background illustration. He is calm and collected in most situations, but his composure is consistently tested by Kashima's antics. His memorable comment about preferring girls with nice legs showcases a rare moment of earnest awkwardness. Overall, Hori is a capable, driven, and layered character whose dedication to his responsibilities and his complex relationship with Kashima provide both comedic and heartfelt moments.