Lune is the crown prince of the Cat Kingdom and appears as a supporting character in the film. He is a Russian Blue cat with a calm and dignified demeanor, contrasting sharply with his father, the Cat King, who is overbearing and impulsive. Lune is portrayed as genuinely kind, humble, and respectful toward others, showing no interest in the grandiose plans his father concocts on his behalf. His primary motivation is to honor his own feelings and do what is right, rather than follow the King’s will. In the story, Lune’s role begins indirectly: Haru Yoshioka saves him from being hit by a truck, an act that sets the entire plot in motion. The Cat King, as a gesture of gratitude, decides that Haru must marry Lune, but Lune is away from the kingdom during most of the events and unaware of this arrangement. When he returns near the climax, he reveals that the King was not acting on his behalf and that he has no intention of marrying Haru. Instead, Lune announces his wish to propose to Yuki, a white cat maiden who had helped Haru escape. This act resolves the central conflict and demonstrates his integrity. Key relationships include that with his father, whom he opposes by refusing to go along with the forced marriage, and with Yuki, whom he genuinely loves. He also shows gratitude and respect toward Haru, though he does not interact with her extensively. Lune does not display any supernatural abilities beyond those typical of talking cats in the kingdom; his notable traits are his principled nature, his loyalty to Yuki, and his willingness to correct his father’s mistakes. His development is subtle, as he is already mature and principled from the start, stepping into a decisive role only when needed.