The supreme ruler of the Cat Kingdom. A Persian cat with a grand physique. Selfish and egocentric. Father of Prince Lune. He overwhelms Haru with excessive "favors" (like gifts of mice and forcing her into marriage) after she saves his son Lune from an accident, much to her distress.

The protagonist. She has a bright, straightforward, and honest personality. While she has no extraordinary talents, she has no major flaws either and lives an ordinary life. She is kind-hearted, as seen when she saves a cat from being hit by a car. She struggles with mornings and has a clumsy side, often oversleeping or being late. Throughout the story, she shows the strength to break away from her tendency to go with the flow and firmly chooses her own path.

A large, stout male cat. An important character who guides the protagonist, Haru. Though he can be blunt, short-tempered, and foul-mouthed, he subtly helps Haru when she's in a pinch. He is kind at heart. A legendary glutton who is said to have once eaten every single fish in the kingdom.

A beautiful Russian Blue cat (notable for his heterochromia). He is in love with Yuki and becomes engaged to her toward the end. He was saved by Haru when he ran out into the road. Gentlemanly and considerate, he shows concern for Haru when she is confused upon arriving in the Cat Kingdom.

A female cat who lives quietly in the palace of the Cat Kingdom. She becomes engaged to Lune at the end. A vital character who gives advice to Haru when she is about to be taken to the Cat Kingdom. When Haru was in elementary school, she fed fish-shaped cookies to a starving Yuki.

An advisor-like subordinate who stays by the Cat King's side. A male cat. He maintains a deadpan expression, occasionally showing surprise.

Natori's subordinate. A female cat. She is cheerful, but can be a bit of a klutz when she panics.