Moonfish is a villain affiliated with the League of Villains, serving within its Vanguard Action Squad. He possesses a fair complexion and black eyes, typically concealed by restrictive attire. Initially, he appears confined in a black straitjacket covering his entire body except for his mouth, secured by spiked restraints and metal clamps forcing his lips open. After imprisonment and escape, his attire changes to include a spiked collar covering his eyes, a harness, spiked pants, and a chained spiked ball. He exhibits extreme psychosis characterized by a consuming obsession with human flesh. Moonfish engages in repetitive self-dialogue, frequently vocalizing his struggle to maintain focus on tasks due to the overwhelming allure of flesh. This obsession drives indiscriminate violence; he attacks both enemies and allies to satisfy his cravings. His volatile temper surfaces when denied access to perceived "prizes," such as targeted victims. His motivations appear self-serving, primarily seeking opportunities for carnage rather than ideological alignment with groups like the League of Villains. His criminal background places him on death row for unspecified atrocities deemed exceptionally vile. A denied appeal preceded his prison escape, leading to his recruitment by the League. Post-escape activities include participation in the Forest Training Camp attack, where he severed Mezo Shoji's arm and engaged Katsuki Bakugo and Shoto Todoroki. He exploited environmental conditions, specifically a forest fire, to limit their fire-based Quirks, wounding Todoroki before Fumikage Tokoyami's uncontrolled Dark Shadow overpowered him. Dark Shadow shattered his teeth and hurled him into terrain, resulting in his capture alongside Muscular and Mustard. Subsequent imprisonment occurred in Tartarus. During the prison break orchestrated by Tomura Shigaraki and All For One, Moonfish indiscriminately slaughtered guards and inmates while escaping. He later joined the Final War, fighting on Okuto Island where he engaged in brutal assaults against heroes before being recaptured. His combat proficiency stems from his Quirk, Blade-Tooth, allowing elongation, manipulation, and propulsion of his teeth into bladed projectiles. These exhibit exceptional sharpness and durability, capable of piercing soil, ice, and flesh effortlessly. He employs them for mobility—using teeth as limbs for rapid traversal—and for long-range assaults. Enhanced speed and reflexes enable evasion of attacks even while restrained. His prowess earned recognition from Kai Chisaki as a "first-rank villain" alongside Muscular and Stain. Stat assessments note high speed (5/5) and technique (5/5), but low intelligence (3/5) and cooperativeness (1/5). Post-Final War, his execution is implied though unconfirmed.