The character Sphinx's Daughter first appears as Piro in the manga chapter "The Tale of the Fangs of Athens." This young sphinx has a green mane and beige body. Her mother, the Sphinx, delivers the unconscious Unico as food, but Piro rejects eating him, declaring a preference for spaghetti and commanding Unico to dance. After Unico collapses from exhaustion, Piro revives him with nourishment and facilitates his escape. Later, when Oedipus mortally wounds the Sphinx, Piro sinks into despair until Unico returns to relay the news and inspire resilience, signaling her shift from vulnerability toward courage. In the film *Unico in the Island of Magic*, the character is reimagined as Marusu (credited as "Sphinx's Daughter" or "Mars"). She retains Piro’s beige fur, feline traits, and pointed ears. Discovering Unico and the human child Cherry collapsed in the desert, she shelters them. Learning of their quest to overthrow the sorcerer Kuruku, she willingly joins their journey to the "Ends of the Earth." Unlike her manga counterpart, Marusu displays inherent fearlessness and curiosity, engaging directly in the mission without personal crisis. The 2024 reboot *Unico: Awakening* reintroduces her as Marusu, confirming her as the Sphinx’s offspring. Expanded background reveals Venus abducted her—a detail disclosed during the Sphinx’s dialogue with the West Wind. This abduction serves as a catalyst for the Sphinx’s role in Unico’s destiny, though Marusu’s direct involvement or development in the reboot remains confined to this setup. No further appearances or developmental arcs exist in other animated media.