Mayu Nekoyashiki is a second-year middle school student who has recently moved to Animal Town. She is the devoted owner of a white cat named Yuki, whom she rescued from the cold several years before the events of the story. Mayu is characterized by her shy and introverted nature; she longs to make friends but often retreats from social interaction due to anxiety. Despite this, she possesses a gentle and kind heart, and she finds comfort in expressing herself through creative activities such as handicrafts, sewing, and applying makeup. Her passion for making things extends to a love of knitting, and she enjoys creating items that bring happiness to those around her.

When she transforms into Cure Lillian, Mayu gains a softer, more confident demeanor that allows her to act on her courage. Her transformation is triggered by her desire to protect Yuki and her new friends, marking a turning point where she begins to overcome her shyness. As Cure Lillian, she wields the Shiny Cats Pact and uses techniques such as the Lillian Net, which she employs to purify rampaging creatures known as Garugaru by earning their trust rather than fighting them aggressively. She also has access to defensive skills like the Puni Puni Barrier, Ribbon Barrier, Nyammy Shield, and the Help! Kirarin Animal! ability.

Mayu’s key relationships are central to her growth. Her bond with Yuki is the deepest; Yuki was a stray cat she rescued, and the two share a sisterly partnership after Yuki gains a human form and becomes Cure Nyammy. Mayu often confides in Yuki and draws strength from her presence. She also becomes close friends with Iroha Inukai and her dog Komugi (Cure Wonderful and Cure Friendly), who help her step out of her shell. Mayu is supportive of Satoru Toyama’s feelings for Iroha and frequently encourages him, showing a playful, teasing side.

Throughout the series, Mayu develops from a socially anxious girl who hides from the world into a confident young hero who uses her kindness and creativity to protect others. Her journey emphasizes self-acceptance and the power of gentle courage. In the movie Wonderful Precure! The Movie!: Dokidoki Game no Sekai de Daibouken, she continues to stand alongside her fellow Cures, applying her handmade skills and newfound bravery to overcome challenges in a game-like world. Her notable abilities combine crafty precision and empathetic purification, making her a unique and valuable member of the Precure team.