Posi is one of two cat-like creatures from the planet Feather Star who appear in Magical Angel Creamy Mami: Curtain Call. Along with her companion Nega, Posi was entrusted with watching over Yuu Morisawa during the time Yuu held magical powers, and in Curtain Call she continues in that role as Yuu is drawn back into contact with the magical world and her idol persona Creamy Mami.

Personality-wise, Posi is warm, bright, and consistently encouraging. She shows strong support for Yuu and the choices Yuu makes, a trait that frequently irritates Nega and can annoy her fellow companion. The pairing of an upbeat, supportive Posi with a more irritable Nega forms the core of their relationship, with Posi often acting as the reassuring half of the duo.

Posi's motivation is anchored in genuine care for Yuu and a sense of duty to look after her. Her role in the story is that of a loyal guardian and companion rather than an instigator of events; she remains close to Yuu throughout the work, offering emotional backing and steady presence as Yuu faces the challenges connected to her magical identity.

As a native of Feather Star, Posi belongs to the same otherworldly origin as the story's magical elements, but her notable abilities lie less in overt magic and more in her function as a devoted observer and caretaker. Her development across the story is expressed through her constant loyalty: she is a dependable figure who does not waver in her support of Yuu, providing continuity and warmth amid the events of the narrative.