Name: Leviathan Reiji Gender: Male Appearance: A young man with short blue hair and long bangs that cover his eyes. He always wears a white uniform and a hat. First person: I (formal/polite) Second person: You (blunt/arrogant) / You (polite) / -sama (for superiors) Title: Commander-in-Chief (by students) Occupation: Second-year student at Demon Sea Academy Rebialon and Student Captain Rank: Vau (6) Bloodline Ability: "Dekisui" (Drowning Love). He can command and control all forms of moisture. He uses a "Super High-Performance Water Gun," a family heirloom weapon, to manipulate and fire water at will. Family: Lady Levi (Grandmother) Personality: Despite his polite language and demeanor, he is dogmatic, arrogant, and acts solely according to his own personal discipline. <Dialogue Examples>: "Go forth, Dekisui." / "It is I who should become the Demon King."

Grandson of Lady Levi, one of the Three Heroes. One of the candidates for the next Demon King. He is doted on by his grandmother, who brags about him at the Three Heroes meetings, calling him the "pride of the family" and "the supreme grandson," and even takes photos of him during his interview with the 13 Crowns. At the prestigious Demon Sea Academy Rebialon, where his grandmother is the headmaster and values discipline and upright behavior above all else, he committed the audacity of arriving two hours late to the entrance ceremony due to oversleeping, only to start his speech as if nothing happened. He has earned countless nicknames like "Unauthorized Bombardment," "Gatekeeper Slayer," and "Guerrilla Sculptor." However, he possesses enough charisma and skill to be called the Commander-in-Chief by the students. The Netherworld he wants to create as Demon King is a "disciplined yet free world where every demon follows the rules I have made." Contrary to his appearance, he eats food by grabbing it with his hands and devouring it voraciously. According to him, this is the only legitimate way to eat.