Gennai is a data-based humanoid entity serving as a guide and caretaker within the Digital World. He co-created the Digivices, Crests, Tags, and Partner Digimon for the DigiDestined. His group was attacked by Piedmon, who slaughtered his comrades and stole the Tags and Crests. Gennai escaped but lost Kari Kamiya's intended Digivice and Digi-Egg; during his escape, Piedmon implanted a mysterious black object, described as a "seed of darkness," into him to restrict his movements or corrupt him. Initially appearing as an elderly man with a grey mustache, nearly bald head, and perpetually closed eyes, Gennai later transformed into a younger form featuring short brown hair, a ponytail, indigo eyes, and brown/cream robes. This transformation may connect to the dark object's influence or his ability to replicate himself, evidenced by multiple international counterparts appearing during a global crisis. After the events of *Digimon Adventure*, he requested the original DigiDestined relinquish their Crests' power to bolster the Digital World's defenses. In later years, Gennai collaborated with human governments, providing intelligence on infected Digimon threats. During the *tri.* series, allies of King Drasil captured him and placed him in stasis alongside the 02 DigiDestined. A corrupted counterpart, "Dark Gennai" (or "Mysterious Man"), emerged, displaying allegiance to Yggdrasil. This dark variant adopted Ken Ichijouji's "Digimon Emperor" guise and unleashed an infected Imperialdramon to abduct Meicoomon. The corruption likely stemmed from the dark object implanted by Piedmon, effectively splitting Gennai into two entities: one imprisoned and one serving antagonistic forces. In *Last Evolution Kizuna*, set five years after *tri.*, Gennai appears briefly to Tai and Agumon. He confirms researcher Menoa Bellucci's findings regarding the inevitable separation of DigiDestined from their Digimon partners as humans reach adulthood and lose their "infinite potential," stating this fate is unavoidable. His broader history includes aiding DigiDestined against threats like Etemon, Myotismon, and the Dark Masters, modifying Izzy's computer for interdimensional communication, distributing Azulongmon's DigiCores, and returning Gatomon's lost Tail Ring to enable Jogress Evolution.