Mr. Cat is an anthropomorphic cat ballet instructor at Gold Crown Academy, dressed formally in a suit and tie. His fully feline, humanoid appearance notably surprised his Japanese voice actor during initial production. He teaches ballet, frequently criticizing students like Ahiru (Duck) for clumsiness and lack of concentration. His eccentric personality manifests through recurring threats of marriage to misbehaving female students, particularly Ahiru, should they fail to improve behavior or punctuality. Despite these quirks, he demonstrates competence as an instructor, offering guidance during pivotal moments. He maintains a consistently dramatic, exaggerated demeanor for comedic relief. His antics, including sudden behavioral shifts when marriage is mentioned, are intentionally over-the-top as directed. This positions him as a source of levity amid darker themes, though his role remains peripheral to the central plot. No substantial character development, backstory, exploration of origins, motivations, or personal history beyond his teaching position is provided across any media. His traits and role remain static. In the anime's conclusion, he appears transformed into an ordinary cat alongside a female cat companion. The manga adaptation retains his role and personality identically. Neither adaptation elaborates on this transformation or expands his background.