Higepiyo is a diminutive yellow chick marked by conspicuous facial hair resembling a van dyke beard or mustache, a trait central to his name and visual identity. Acquired by a boy named Hiroshi at a summer festival stall, the vendor sold the chick despite its unusual appearance and later contacted Hiroshi's family to enforce a no-refund policy after witnessing its human-like behaviors.

Background suggests Higepiyo is likely an escaped laboratory experiment with implied human DNA hybridization, explaining his anthropomorphic traits. This genetic origin accounts for his emergent ability to speak shortly after joining Hiroshi's household.

He exhibits distinctly human mannerisms: consuming curry with a spoon, drinking from a glass, demanding second servings by tapping utensils, reading newspapers, snacking on squid, scratching while watching news, and showing intoxication near sake bottles. Higepiyo demonstrates a strong preference for period dramas and samurai shows.

His personality combines bold protectiveness toward Hiroshi—intervening against bullies, teaching fighting techniques, and stealing bento boxes—with a paradoxical command over neighborhood cats and crows versus intense fear of amphibians, specifically triggered by their fingertip suction disks.

Within Hiroshi's family, Higepiyo integrates fully: sharing meals, attending school, and controlling television viewing. He maintains a close friendship with Hiroshi while displaying gluttony, mischief, and occasional surreal capabilities consistent with experimental origins.