Mepple hails from the Garden of Light as the designated protector of Princess Mipple, sharing a profound bond with her. To conserve energy while in the human world (Garden of Rainbows), he and Mipple adopt efficient forms resembling cellphones, known as Card Communes or later Heartful Communes. He frequently appends "-mepo" to his sentences. Physically, Mepple appears as a small fairy with lemon-yellow fur, navy-blue eyes featuring light blue highlights, bearlike ears, and a star-shaped tail tip. A stylized male gender symbol with heart motifs marks his forehead. His personality carries an arrogance rooted in his status as a chosen warrior, leading him to expect deference and luxury. This often sparks heated arguments with his primary caretaker, Misumi Nagisa, whom he openly criticizes and calls easily manipulated. Despite this friction, he demonstrates genuine concern for her well-being, forging a strong bond over time. His central relationship with Mipple displays marked gentleness and devotion. This dynamic encounters challenges with the arrival of Pollun, the Prince of Light, as Mepple exhibits jealousy over Mipple's attention toward Pollun. He gradually assists Pollun's maturation by teaching him human traditions like Christmas. Mepple also shows protectiveness toward other Garden of Light royals, including Princess Lulun. Dispatched to Earth during the initial Dotsuku Zone invasion to locate the legendary warriors Pretty Cure, Mepple reunites with Mipple and facilitates Nagisa and Yukishiro Honoka's transformations into Cure Black and Cure White. His adjustment to human life proves difficult; severe stress-induced illness strikes him, from which he recovers through Nagisa's intervention. He maintains a pattern of selfish demands, especially regarding food, alongside moments of courage—such as confronting the villain Ilkubo to shield Mipple. Following the Evil King's defeat, Mepple and Mipple face repatriation to the Garden of Light. Choosing eternal sleep to remain with their human partners, they bid emotional farewells before deactivation. They revive during the Max Heart arc when the Queen's life is endangered, resuming their roles as transformation devices. In the final battle against the resurrected Evil King, Mepple reaffirms unwavering loyalty to Nagisa, declaring no regrets about their journey. After the Evil King's defeat, the pair gain permanent residence in the Garden of Rainbows without adverse effects. Within the *Precure All Stars DX: Minna Tomodachi—Kiseki no Zenin Daishūgō* crossover film, Mepple participates alongside other mascots when collective remnants of past enemies form the entity Fusion. He assists Nagisa, Honoka, and Kujou Hikari during Fusion's attack in Minato Mirai, supporting their transformations and battles. When Fusion overwhelms the Pretty Cure teams, Mepple and the other mascots wield the Rainbow Miracle Lights—devices channeling collective hope—to empower the warriors, enabling Fusion's defeat. His characteristic complaint about hunger surfaces post-victory. Mepple also appears fleetingly in episode 38 of *Mahou Tsukai Pretty Cure!*, indicating his enduring presence across the franchise.