Zuruko Sasuga, known internationally as Tigerlily Sakai, is Yuna Kamihara's cousin who debuts midway through the anime's second season, "Stitch! ~The Mischievous Alien's Great Adventure~". She displays a harsh, bullying attitude towards Yuna, frequently forcing her into household chores through blackmail or intimidation and earning the nickname "Tiger the Tyrant". Around others, she maintains a sunny disposition, concealing her true behavior. Her relationship with Yuna is mutually antagonistic; Yuna retaliates by disrupting Zuruko's naps or exploiting her fear of lightning. Zuruko openly expresses fondness for Stitch, though never directly to him. She justifies her treatment of Yuna as being a role model, assigning chores as punishment for Yuna's poor grades and threatening to report misbehavior to their grandmother. In the third season, "Stitch! ~Best Friends Forever~", following Yuna and Stitch's relocation to live with her in Okinawa New Town, Zuruko becomes somewhat friendlier but continues enforcing Yuna's chore duties. Despite their conflicts, underlying care exists: Yuna shows genuine concern, including hugging her, while Zuruko prioritizes Yuna's safety and has made personal sacrifices for her—sacrifices she later uses to manipulate Yuna into more chores as "repayment". Zuruko possesses an intense aversion to being perceived as old, reacting with visible anger or an intimidating aura. In one episode, her likeness manifests as the embodiment of Yuna's worst fear.