Leonhard Saijo, most commonly referred to by the nickname Leo, is a student at First High School enrolled in Course 2, the lower-performing academic track known as the Weeds. He is a close classmate of Tatsuya Shiba, sharing the same classroom during their first year. Physically, Leo possesses chestnut-brown hair, green eyes, and an athletic build that becomes more muscular and sturdy as high school progresses. His facial features are deeply sculpted and give him a distinctly Western appearance, contributing to a lively and energetic aura that attracts a degree of popularity among female students. In terms of personality, Leo is easy-going, bright, and possesses a frank and direct attitude. This straightforwardness often leads him into heated but good-natured arguments with fellow classmate Chiba Erika. He is also known to be easily persuaded and willing to do favors for others, showing a loyal and cooperative side. His primary motivation stems from a desire to prove himself physically and to support his friends in combat situations. Leo’s role in the story is that of a reliable physical combat specialist. He frequently participates in school events such as the Nine Schools Competition, where he is chosen by Kirihara to test experimental weapons and later serves as a partner in the Monolith Code event. As the series progresses, he becomes a club manager for the Mountaineering Club and later acts as a trainer for younger students. In later arcs, particularly during the Visitor Arc, he evolves into a capable fighter against supernatural threats like the Parasites. After graduating high school, Leo attends Katsuwa Rescue University, an institution dedicated to training high-level personnel for rescue operations, indicating a future career in emergency response. In terms of abilities, Leo’s magical specialty is Fortification magic, a type of magic that dramatically enhances his physical durability and strength. This, combined with his natural combat instincts, makes him an overwhelming hand-to-hand fighter. He relies on brute force and resilience rather than complex magical techniques, compensating for his lack of elite academic status with raw physical power and tenacity. His key relationships include a strong friendship with Tatsuya Shiba, a frequent bickering dynamic with Erika Chiba, and a cooperative partnership with Kirihara during competitions. Throughout the series, Leo develops from a straightforward brawler into a more disciplined and reliable warrior, though he retains his cheerful and direct nature.