Guillaume de Malatesta XIII is a genetically engineered cat that has a special unstable muscle fortifier that can have the potential to make her go berserk. She loves cheesecake and wears a red ribbon around her neck. She debuted in the episode "Pursuit Has the Smell of Cheesecake and Death" but is seen in the opening theme "Ru-Ru-Ru-Russian Roulette" being chased by Yuri through a crowd. The Lovely Angels were put on a mission to find her and bring her back to the Bio-Science Research Facility. While the cat managed to get away from both of them even hiding in the apartment of the newly wedded couple Romeo and Julietta. While also being chased by the two famous female wrestlers Lan and Jerry, she eventually got away from both pairs far enough that they ended up chasing a male cat that looks just like her instead. Mughi on the other hand was able to locate her but then faced her in a stand off that ended with an unknown result.