Zirconia appears as an ugly, insect-like old woman with lavender skin. She is second in command to Queen Nehellenia and controls both the Amazoness Quartet and the Amazon Trio. Her name originates from zirconium dioxide, commonly known as zirconia. Zirconia first appears in Episode 128 of the anime and Act 34 of the manga. In the English-language adaptation, her gender was changed from female to male.
In the anime, Zirconia embodies what Queen Nehellenia would look like if she were old, haunting the queen's dreams. She represents Nehellenia’s nightmares, given form to lead the Dead Moon Circus in their quest to find Pegasus and execute the queen's revenge. Zirconia commands the Amazon Trio to search for individuals with beautiful dreams that might contain the Dream Mirror where Pegasus is hiding. Using Zircon, a flying eyeball perched on her staff, she collects images of those with beautiful dreams to provide targets for the Amazon Trio. Growing impatient with the Trio's failures, she permits the Amazoness Quartet to dispatch lemures to eliminate them and then assigns the Quartet to complete their mission.
In the manga, the Amazon Quartet refers to her as "baa-san," meaning "grandmother" or "old woman." She serves as a mediator between them and Nehellenia. Like other members of the Dead Moon Circus, she dislikes light and feels most comfortable in darkness. She communicates with Nehellenia through a mirror, often offering compliments. While little is revealed about her motivations, her primary focus is figuring out how to make Nehellenia's plans succeed. Her initial task for the Quartet is ensuring the circus's success on Earth and gradually taking over everything for the Dead Moon Circus. She advises caution when dealing with the Senshi and makes it clear she won't tolerate failure. To conquer Earth, she insists they must first destroy the Senshi by filling them with nightmares.
