Marusu, the Sphinx's daughter, boasts a spunky and energetic personality. She displays distinct feline features, including prominent fangs, and exhibits cat-like mannerisms such as the "kitty butt wiggle." Her central role involves aiding Unico and Cheri in their mission to confront Lord Kuruku and prevent living beings from being transformed into puppets. She guides the protagonists through the desert, leading them to the Trojan Horse located at the "Ends of the Earth." This site accumulates discarded objects, and the Trojan Horse itself reveals crucial information: Kuruku originated as a mistreated puppet brought to life by centuries of sunlight exposure. Marusu expresses enthusiasm upon learning their destination is Nightmare Island, remarking that it "sounds like my kind of place." Her involvement remains primarily supportive, facilitating the protagonists' quest.