In the 1979 stop-motion anime film Nutcracker Fantasy, the character most commonly associated with the role of a Mouse King is the two-headed rat queen named Morphia. She serves as the primary antagonist of the story. Morphia is the leader of the mice and commands a large army of rodent subjects. She possesses a formidable and cunning personality, driven by a desire for power and revenge. Her motivations stem from a long-standing war between the mice and the Doll Kingdom, which ended with the dolls surrendering. However, Morphia’s final demand—that Princess Mary, the daughter of King Goodwin, must marry her son Gaar—was refused. In retaliation, she placed a curse on Princess Mary, transforming her into a hideous mouse-like creature and casting her into an enchanted sleep that could only be broken if the king agreed to the marriage.

Morphia’s role in the story is that of a tyrannical ruler who seeks to dominate the Doll Kingdom through manipulation and dark magic. She is the driving force behind the conflict that Clara, the protagonist, must help resolve. Morphia’s key relationship is with her son Gaar, whom she intends to elevate to royalty through the forced marriage. She also has a direct adversarial relationship with Franz, the captain of the guard, who ultimately leads an attack against her forces. Morphia’s primary source of power is the Nut of Darkness, a magical object that sustains her strength. She is vulnerable only when this nut is destroyed, and she can only be defeated by a person of pure heart wielding the Sword of Pearl. Upon her defeat at the hands of Franz, who destroys the Nut of Darkness, she utters a dying curse that transforms him into a nutcracker doll. Morphia does not undergo any redeeming development; she remains a malevolent and unyielding villain throughout the film. Her notable abilities include powerful curse magic, the command of a vast army of mice, and the use of the Nut of Darkness as a source of supernatural power.