Piyo-tan embodies the Rooster as the tenth Eto-shin of the Chinese zodiac and serves as the guardian deity of the Tohoku region. She possesses long, wavy light blue hair extending past her hips, sharp red eyes, and stands 178 cm tall. Distinct avian traits include two wings protruding from her head and a large, light green feathery tail. Her signature attire features a black leotard with white accents at the breasts and cyan feather-like frills along the abdomen, detached cyan sleeves, navy leggings, and brown knee-high boots adorned with cyan frills. A pink ribbon circles her neck.

Typically projecting a mature and composed aura, Piyo-tan harbors a quick temper, easily provoked. This irritability stems directly from her inherent short-term memory limitation: taking three consecutive steps completely erases her recent memories. However, the emotions linked to those forgotten events linger and accumulate within her, particularly negative feelings. This results in persistent, unexplained resentment, most often directed at Nyaa-tan, the Cat Eto-musume. Their relationship is defined by mutual antagonism; Nyaa-tan frequently exploits Piyo-tan's condition, deliberately provoking her anger and then causing her to take three steps. This makes Piyo-tan forget the specific incident while leaving behind only intensified frustration.

To cope with this accumulating emotional burden, Piyo-tan turns to shogi. She is a highly skilled and passionate player, finding the game deeply therapeutic. Playing shogi allows her mind to achieve a state of emptiness, providing respite and restoring her sense of self. Her core wish is to overcome her memory constraint.

In the ONA *Etotama: Nyan-Kyaku Banrai*, Piyo-tan appears among the assembled zodiac deities, demonstrating no significant changes to her established traits, relationships, or role. Her narrative function consistently centers on her zodiac role, memory limitation, and combative dynamic with Nyaa-tan.