Fuwa begins as an infant entity crafted by the twelve Star Princesses, a final cosmic safeguard against the Notraiders' invasion. Designed with a fluffy mouse-like form, star-adorned features, small wings, and speech ending in "~fuwa", her physiology enables interdimensional travel through warp hole generation—essential for tracking scattered Star Princesses across the universe.

Exhibiting childlike curiosity and vulnerability, she bonds deeply with guardians Hoshina Hikaru, Hagoromo Lala, Amamiya Elena, Kaguya Madoka, and Yuni, though her naivety occasionally leads to capture by antagonists. After facilitating the Star Princesses' revival, she evolves into a permanent unicorn form, gaining abilities like projecting rainbow energy for group purification attacks (Star Twinkle Imagination) and precise spatial warping, though initial warps often yield erratic destinations.

Her development peaks during the confrontation with Ophiuchus, where she self-sacrifices by absorbing accumulated Twinkle Imagination to neutralize a black hole threat. This erases her existence temporarily, but collective imagination from her guardians and universal beings later restores her infant form with fragmented memories and lost powers. A 15-year epilogue confirms her regained teleportation abilities and emotional connection to Hikaru, observed as a symbolic shooting star during Hikaru's space mission.

Within the *Miracle Universe* film, Fuwa accompanies the Star Twinkle team after an accidental warp to Miracle Light planet. She supports the Cures against a darkness-consuming entity without new transformations or power displays, maintaining an auxiliary role emphasizing loyalty during multiversal crises.

Pre-unicorn stages include Zodiac-inspired temporary forms reflecting astrological traits—from Aries' woolly crimson look to Pisces' mermaid-like tail—manifested when accessing constellation energies to locate specific Star Princesses. Post-rebirth, she retains her core identity while symbolizing enduring hope across spacetime.