Mofu is a mysterious cat from the otherworldly realm known as the Thousand-Year Fortress, a central setting in the film. Unlike ordinary animals, Mofu can speak human language and possesses a keen understanding of the strange, time-stopped world. She becomes the new partner of the young protagonist, Lubicchi, after he accidentally wanders into this realm. Mofu’s role is primarily that of a guide and companion, helping Lubicchi navigate the fortress and understand its rules. She is motivated by a practical bargain: the queen of the fortress, Hora, offers to reduce Mofu’s workload of clock deliveries if she assists Lubicchi in restarting the great clock tower, which has been frozen at 11:59 for over a century. Over the course of the adventure, Mofu evolves from a somewhat sardonic, task-oriented helper into a brave and loyal ally. She provides much of the film’s lightness and humor, balancing the heavier themes of grief and waiting. Her ability to speak and her familiarity with the fortress’s inhabitants, such as the clockmaker Gus and the enigmatic Nagi, make her invaluable in uncovering the emotional mystery behind the stopped clock. Mofu’s relationship with Lubicchi is built on mutual trust and growth; she helps him rediscover faith and courage, while he helps her move beyond her initial cynicism. Her design is whimsical and distinctly feline, fitting the surreal aesthetic of the frozen world. Mofu has no special combat abilities, but her cleverness, knowledge, and steadfast presence are crucial to the quest. Ultimately, she is a key catalyst for Lubicchi’s character arc and for the resolution of the story’s central promise.