Josephine is a character from the anime Nyan Koi!. He is a cat owned by Nagi Ichinose, an upperclassman of the protagonist Junpei Kousaka. Described as a male with brown hair and blue eyes, Josephine is often depicted wearing a collar with a bell and frills.

Josephine serves as a supporting character who is deeply concerned with the well-being and happiness of his owner, Nagi. His primary motivation is to see Nagi find love and become more confident in her femininity. Living in a mansion owned by a yakuza family, Josephine observes Nagi's struggles, particularly her boyish appearance and her unrequited feelings for Kaede Mizuno, a classmate of Junpei.

Josephine's key role in the story occurs during a specific incident. After Junpei, Kaede, and another friend bring an unconscious Nagi to her family home during a rainstorm, Josephine approaches Junpei with a direct request. The cat asks Junpei to help make Nagi fall in love, demonstrating his proactive nature and his understanding of human emotions. This request is significant because Junpei is under a curse that forces him to fulfill one hundred wishes from cats, or else he will turn into a cat himself. Therefore, Josephine's wish becomes a task that Junpei must complete.

Notable abilities include Josephine's capacity to speak with Junpei, who gained the ability to understand cats after breaking a cat deity statue. Through this communication, Josephine reveals his intelligence and his strategic thinking in using Junpei's curse to improve Nagi's life. The character shows development in his relationship with Nagi as a caring and observant pet who takes action to influence human affairs for her benefit, as seen when he expresses satisfaction after Junpei successfully calms Nagi during a lightning storm, leading to a resolution he had hoped for.