Manaka is an anthropomorphic chinchilla with pale turquoise fur, large light brown eyes, three whiskers on each cheek, and a long thin tail. She consistently wears a white and pink plaid bow atop her head, complemented by a matching schoolgirl-style outfit: a white top featuring a central plaid bow, a coordinating skirt, long white socks, and shoes.

Initially introduced as a store clerk and lead singer of the idol group OTM Girls, Manaka exhibits an impertinent, arrogant, and impatient demeanor in early interactions. She demonstrates fierce dedication to her idol career, displaying a strong work ethic and relentless drive to achieve her goals. Her central positioning within OTM Girls performances reflects her name's linguistic origin in the Japanese word "man'naka," meaning "center."

Manaka's primary development unfolds through her evolving relationship with Retsuko. Initially demanding and dismissive toward Retsuko upon her joining OTM Girls, Manaka gradually cultivates genuine appreciation and respect for her. This progression transforms their dynamic from professional acquaintances to trusted friends who confide in personal struggles and offer mutual advice. Manaka further displays protective loyalty toward Retsuko, arming herself with a modified baseball bat alongside group bodyguards to confront perceived threats like Retsuko's unhinged fan or Masuo Ikari.

Beyond idol activities, Manaka exhibits visible annoyance toward Director Ton over his habitual reliance on an abacus instead of modern barcode readers and his repeated forgetfulness of her instructions. Her relationships with fellow OTM Girls members Migi and Hidarin remain significant, though detailed descriptions are unspecified in available sources.