Leviathan is the third-born of the seven demon brothers in Obey Me! and the Avatar of Envy. Once an angel and a general of the Celestial Realm's army, he lost his sense of purpose after peace was established and later followed Lucifer during the Celestial War, becoming a demon after their defeat. Though powerful enough to summon the sea serpent Lotan and skilled in combat, Levi now spends most of his time shut away in his room indulging in his hobbies rather than seeking glory. A stereotypical otaku and hikikomori, Leviathan is obsessed with anime, manga, video games, and the fictional series The Tale of the Seven Lords (TSL). He dreams of becoming a professional gamer, enjoys cosplay, and is talented at sewing his own costumes. His room is packed with collectibles, gaming consoles, and merchandise, and he adores his pet goldfish, Henry. Levi has a strong dislike for "normies," believing they could never understand his interests, and often keeps others at arm's length because of it. As the Avatar of Envy, Leviathan constantly compares himself to others and almost always comes up short in his own mind. He frequently calls himself a "worthless otaku" and struggles with deep feelings of inferiority, assuming people dislike him before they have the chance to prove otherwise. His jealousy can make him irrational or hot-tempered, but beneath the insecurity is a surprisingly kind, loyal, and emotionally sensitive person. Once someone earns his trust, he becomes fiercely devoted and enjoys sharing his passions with them, especially if they're willing to marathon anime or play games together. He loves the fictional magical girl Ruri-Hana (often referred to as Ruri-chan). He is a tsundere. He likes anime music and technopop, and follows multiple idol groups. He sleeps in a bathtub in his room instead of a bed. His usual gamertag he goes by online is Leviachan. He's a student at the Royal Academy of Diavolo (RAD). He is also the Grand Admiral of hell's navy, an honor granted by Diavolo, prince of the Devildom. He has indigo hair and orange eyes. In his demon form (only present when he uses his powers or gets VERY angry) he has a snake-like tail with black scales and black horns that resemble coral.