Mai Mishou is a second-year transfer student at Yuunagi Middle School, sharing classes with Saki Hyuuga and later Michiru and Kaoru Kiryuu. Her family lives in an observatory; her father is an astronomer, her mother an archaeologist, and her brother Kazuya aspires to be an astronaut. Mai possesses a calm, serene, and observant personality. She is a top student who notices subtle details in her surroundings and holds a strong passion for both art and science, often sketching meaningful subjects and drawing inspiration from everyday positive experiences.

Mai first met Saki at age nine beneath the Sky Tree during a summer festival, where both saw mysterious lights later revealed as the spirits Flappy and Choppy. Five years later, after moving back to town, she reunited with Saki at the same spot. When the fairy Choppy was endangered by Dark Fall's Karehan, Mai's desire to protect others awakened her transformation ability. Using the Mix Commune device, she became Cure Egret, introduced as "the sparkling silver wing," wielding powers derived from the sky and birds. Her abilities include shaping spiritual energy, creating barriers, and flight. Later, with the Splash Commune and spirits Moop and Fuup, she gained an upgraded form as Cure Windy, introduced as "the scented wind on the earth," commanding wind-based powers. Her ultimate combined form, Cure Rainbow Windy Egret, merges both transformations and features small gold wings.

In her civilian life, Mai has long dark blue hair (often purple in official art), purple eyes, and favors coordinated outfits like cream frilly tops with light blue jackets and cerulean jeans. As Cure Egret, her hair brightens into a ponytail secured by a white bow-adorned band, and she wears a cream mini-dress with feather-like frills and teal heart-shaped accessories. The Cure Windy form alters this outfit to pale cyan and lavender shades with translucent sleeves and pale pink gem accents.

Throughout her story, Mai develops a close partnership with Saki, resolving disagreements through communication and mutual support. She forms a trusting bond with her fairy partner Choppy, who offers consistent emotional encouragement. When Michiru and Kaoru arrive as exchange students, Mai befriends them but later discovers their affiliation with Dark Fall. Despite their betrayal, she and Saki work to protect them from Dark Fall's retaliation after they defect. During the final battle against Goyan, Mai and Saki combine their powers with Michiru and Kaoru's borrowed abilities to execute the Spiral Heart Splash Star attack, defeating Goyan and restoring the Land of Fountains and Land of Greenery.

In the sequel Kibou no Chikara ~Otona Pretty Cure '23~, Mai works as a graphic designer at an advertising agency. Her adult appearance features shorter hair styled in a neat ponytail with an ombre tint, accessorized with wing-shaped earrings and professional attire like peach-pink cardigans with turquoise skirts. She experiences romantic uncertainty when her boyfriend suggests a breakup, leading to self-doubt as she compares her relationships. After encountering Shadows and reuniting with Saki and the Yes! Pretty Cure 5 team, she ends the relationship. Later, noticing Saki's stress, she takes her to the Sky Tree for emotional support, advising her to prioritize personal feelings over assumptions. Following an attack by Bell, Mai helps Saki reignite their transformation abilities to become Cure Egret and Cure Windy again, acknowledging the physical risks of using Time Flowers but choosing to protect the town regardless.

Her name carries thematic significance: "Mishou" combines "beauty" (美) and "soar/fly" (翔), reflecting her avian-themed Cure Egret identity and wind-based Cure Windy powers, while "Mai" (舞) translates to "dance." Cure Egret's name directly references the egret bird, and Cure Windy's name denotes control over wind elements.