Aguni is a character from the original television anime. He is a unique member of the Tesseractor species, which grants him the supernatural ability to manipulate heat at will. This power makes him a highly formidable opponent in any confrontation. His existence is defined by a duality in appearance: his true form is that of a fearsome reptilian monster, but he typically assumes a human form that resembles a rebellious delinquent male, complete with a rough and intimidating look.

Within the setting of the story, Aguni operates as a prominent gangster in the underworld of Kamitsubaki City, moving deftly among the shadows and establishing a dominant presence in its darker corners. He is well-known and influential within this criminal sphere, where he engages in various underground activities. His personality is notably straightforward and cheerful, a demeanor that cuts through complications without pretense or hidden motives. Despite this bright and outwardly simple nature, his approach to combat reveals a rational and aggressively strategic mindset. He genuinely loves the thrill of a good fight and is characterized by an unwavering refusal to back down from any challenge. This combination of a carefree exterior and a battle-hungry, tactical interior makes him a complex figure who is both approachable and dangerous.