OVA
Description
Fafnir, originally a dragon from another world, lived isolated in a cave fiercely guarding his treasure. This fostered intense hatred for invading humans seeking to steal it, leading him to align with the Chaos Faction through shared interests in curses and destruction. His initial disposition was violently murderous and misanthropic, viewing humans as inherently contemptible.

After arriving in the human world, Fafnir debuted as a voice during Tohru's phone call in the series' first episode. He later appeared physically at Kobayashi's party, encountering Makoto Takiya. Takiya introduced him to video games, sparking an intense obsession with otaku culture encompassing gaming, doujinshi, and conventions, which became central to his daily life. This shared interest forged a bond with Takiya, prompting Fafnir to move into his apartment as a roommate, marking the start of his gradual acceptance of human companionship.

His character evolved significantly across media. From initial indifference or hostility, he developed a mentor-student dynamic with Takiya, eventually tolerating nicknames like "Faf-kun" and participating in human activities like Comiket, though his curse-themed doujinshi consistently failed to sell. Further mellowing occurred through group interactions: joining retirement home performances, dodgeball games, and spa outings, though he maintained a reserved, gloomy demeanor. His disdain for humans shifted toward indifference, punctuated by subtle acts of care, like accommodating Takiya's parents after a gaming challenge or lecturing Takiya on familial relationships.

Fafnir possesses a unique triple-form ability: a towering dark dragon with sinuous tentacle-legs and feather-tipped wings; a purple-skinned, horned bipedal demon form; and a human guise resembling a long-haired young man in butler attire, often featuring glasses and a ponytail. His powers include immense physical strength exceeding Tohru's, potent curse-crafting effective on humans without magic, portal creation akin to other dragons, and a lack of need for sleep enabling prolonged gaming sessions.

Relationships highlight his development. Takiya remains his closest human connection; their shared otaku lifestyle forms a "timeless bromance" explored in the spin-off manga *Fafnir the Recluse*. Among dragons, he shares mutual respect with Tohru, whom he advises, and coexists neutrally with others like Elma, Lucoa, and Kanna, showing neither particular animosity nor affection. His dynamic with Kobayashi is distant but mutually respectful, with neither imposing on the other.

Fafnir's mythological roots as a greed-driven figure are reflected in his hoarding tendencies and isolationist past, though his character arc centers on transcending these traits through human connections while retaining his essential nature.