The leader of a cat-worshiping cult called "The Underside of the Kitten's Paw." The grandaughter and heir of a multi-millionare, Antonia was given everything she wanted in life, and so her personality developed to be selfish. After abducting Eris in order to have Eris all to herself, Anotonia begins to realize that simply taking what you want doesn't really lead to happiness, especially when Kio remarks that even though Antoinia has tons of maids and material goods, her life will be empty without any friends.

After Dogishuians attack Antonia's ship, Eris extends an offer to Antonia to be friends for real, prompting a change in her personallity, causing her to be less selfish and haughty. Afterwards, she changes her kitty cult into a more secular organization that simply loves cats.