Blade is the main protagonist of this story, a seventeen-year-old student at Rosewood Academy with a distinctive and memorable appearance defined by his split-colored hair, which is half black and half white. He typically wears the standard school uniform, often accompanied by a sword strapped to his back, and his body bears numerous scars, lasting evidence of the fierce battles he has endured.

His true identity is that of the legendary Great Hero who once defeated the Demon Lord, an event that cost him nearly all of his immense power. Having spent his childhood in constant training and combat, his social knowledge and understanding of ordinary life are severely lacking. This background is the root of his seemingly contradictory nature: he is an incredibly powerful warrior who is also naively innocent and ignorant of basic social conventions.

Personality-wise, Blade is generally simple-minded, carefree, and optimistic, approaching every interaction with an almost dog-like enthusiasm. His primary goal upon enrolling at Rosewood Academy is to experience the normal student life he was denied, with a very specific target of making one hundred friends. He tries to blend in by using his catchphrase, normal, whenever he accidentally performs an extraordinary feat, a tactic that is almost never convincing. However, this cheerful and sometimes perverted or annoying demeanor completely shifts when he enters a serious fight, particularly against diabolical monsters or demons. In these moments, he becomes focused, reliable, and displays the savage, unwavering strength of a true hero, though using his full power can put his own life at risk.

In his role at the academy, Blade acts as an unintentional catalyst for growth and resolution among his peers. His power is so far beyond that of a normal student that he often disrupts classes, such as destroying most of a school building during practical training. He forms a close-knit group of friends, which makes up the core of his key relationships. Arnest Flaming, the Empress of Flames, is his first major acquaintance and primary love interest. Their relationship begins with conflict, but after Blade helps her overcome the corrupting influence of her demonic sword, she falls in love with him, though he remains largely oblivious to romance. Sophie is another crucial figure; she is an incomplete artificial hero with a painful past connected to Blade. Feeling a sense of guilt and responsibility, Blade develops a deep, trusting friendship with her, and she is the first person to learn his true identity. Other relationships include the young dragon girl Cu Chulainn, who views Blade as her parent after he defeats her; Claire, his very first friend at the academy; and Lunaria, an exchange student who mistakenly believes Blade proposed to her due to a cultural misunderstanding.

Throughout the narrative, Blade's development focuses on two parallel tracks. The first is his slow but steady recovery of his lost powers, gradually regaining more of his original strength over time. The second, more central to his character, is his emotional and social growth. He learns what it means to be a friend, confronts the loneliness of his past as the hero, and processes the guilt he carries for those he could not save. His notable abilities, even at a fraction of his former power, are extraordinary. He is an unmatched warrior with incredible physical and combat skills, capable of unleashing powerful attacks from his sword, which is his constant companion. While his power is dormant, he is still far superior to any other student, and as the story progresses, he continues to reclaim his legendary might.