Hailing from Baikin Planet, Baikinman crash-landed on Earth as an egg that hatched simultaneously with Anpanman’s birth, igniting a lifelong rivalry as opposing embodiments of moral dualism. Driven by a relentless quest to overthrow Anpanman and reshape Earth into a "Germ World," he orchestrates schemes ranging from food theft to deploying germ-themed weapons and mechanical contraptions, though his grandiose plans consistently unravel. Blending narcissism, impulsiveness, and tenacity, he ceaselessly boasts of his brilliance while engineering elaborate traps, only to rebound defiantly after each defeat.

In the 2007 adventure *Shabondama no Purun*, Baikinman partners with Horror and Dokin-chan to infiltrate a bubble-themed fortress, stealing enchanted flutes that spawn corrosive bubbles capable of polluting ecosystems. Disguising themselves to infiltrate the castle, they unleash environmental chaos until Anpanman and Purun—a timid bubble performer conquering her insecurities—disrupt their plot and purify the toxins.

Beyond isolated incidents, Baikinman displays flickers of moral ambiguity, notably in a 2018 film where he hesitates to strike Anpanman and aids in rescuing him, unveiling a tension between his destructive mission and flickering empathy. His relationships deepen his narrative: he nurses unreciprocated affection for Dokin-chan, whose devotion lies with Shokupanman, and shares a fractious dynamic with Franken Robo-kun, a pacifist robot he built who rejects battling Anpanman.

Unyielding resilience fuels Baikinman’s persistence, relentlessly reviving schemes after each collapse. His inventions—germ-armored robots and toxin-spewing devices—flaunt his self-proclaimed mechanical ingenuity, though their flaws often trigger self-sabotaging outcomes. Modeled after Beelzebub, the "Lord of the Flies," his fly-like silhouette and germ-centric motif underscore his identity, while his cultural impact resonates in parodies such as *One-Punch Man*’s Vaccine Man.