Mepple is a fairy mascot marked by a distinctive tail and a recurring verbal tic, blending self-centered tendencies with an underlying dedication to his allies. He belongs to a collective of mascots tied to the Prism Flower, a mystical conduit bridging Earth to distant realms. Tasked with aiding the Cures during confrontations, Mepple teams up with fellow mascots to repel threats. When the Prism Flower’s power dwindles, destabilizing their earthly foothold, he devises tactical maneuvers—harnessing mirrors to deflect Miracle Lights, dazzling adversaries like Shadow and creating openings for the Cures to strike.

After the Prism Flower’s collapse severs the mascots’ bonds with their human companions, Mepple persists in aiding his allies despite the emotional strain. Post-victory, a fresh Prism Flower blossoms at the Tree of Hearts, rekindling interdimensional pathways and granting Mepple and his companions renewed access to Earth. His journey highlights resourcefulness in crisis, collaborative resilience, and an unyielding commitment to the Cures amid shifting alliances and multidimensional trials.