Mezool is one of the main antagonists in the tokusatsu series Kamen Rider OOO. She is a member of the Greeed, ancient alchemical beings who seek to regain their lost power by collecting Cell Medals. Mezool represents the aquatic animals and is known for her calm, manipulative nature. She often uses her intelligence to strategize and lead the other Greeed, manipulating humans to further her goals. Mezool's role is pivotal in challenging the protagonist and driving the conflict of the series.