Cosmo Hōjō is a female character with teal shoulder-length hair, featuring bangs that cover one eye, and striking purple eyes accentuated by teal eye makeup. Her cosmic aesthetic shines through planet-themed earrings and space-inspired clothing. As primary guardian for her younger sister Sophy Hojo due to their parents' frequent international travels, she shares apartment 3333 on the 33rd floor of Pride Tower Hills with Sophy.

Professionally, Cosmo is an established fashion designer specializing in Cyalume Coords—signature transformation outfits for idols in the PriPara universe. She crafted these designs for units like SoLaMi♡Smile and Dressing Pafé, drawing inspiration from Prism Sparks encountered during a formative Prism Tour. Beyond design, she occasionally performs as an idol; her debut supported SoLaMi Dressing with the song "Your 100% Life," and she later joined the unit UCCHARI BIG-BANGS alongside Ajimi Kiki and Chanko.

Cosmo exhibits a consistently kind, attentive, and energetic personality, frequently weaving "cosmic" into her speech. She maintains a calm demeanor but reveals playful energy around close associates like longtime friend-rival Ajimi Kiki. Her protectiveness surfaces regarding Sophy’s idol activities.

Born on September 12th—Space Day in Japan—under the Virgo zodiac, Cosmo is noted among few supporting characters to receive an insert song and dedicated visual design. Her appearance remains consistent since Sophy’s earlier idol debut, suggesting mid-to-late twenties age. She previously appeared as a teenage character in *Pretty Rhythm: Rainbow Live*, depicted with competitive, standoffish traits and gyaru-style slang, serving as a rival in the *Pretty Rhythm Rainbow Live: Kira Kira My☆Design* game.