Sis, age 32, oversees operations for Eden, a group formed to support 20,000 NEETs relocated to Dubai after they helped prevent casualties during the Careless Monday missile attack. She displays enthusiastic behavior and unconventional erotic preferences that unsettle some Eden members. Her role extends beyond supervision; she actively assists Eden leader Kazuomi Hirasawa by encouraging and coaxing him in managing the group's initiatives. Sis has attended classes across multiple university departments without holding formal student status. Following the initial series, Eden evolves into a formal business entity operating from a Toyosu shopping mall. Sis remains a core team member, focusing on leveraging technology for social networking and information gathering. She participates in monitoring activities related to the Seleção game and its participants who access resources via the concierge service Juiz. During this time, Sis is involved in efforts to locate Akira Takizawa, a central Seleção figure who disappeared after erasing his memories. Six months later, during *The King of Eden* events, Sis continues her Eden involvement. She contributes to tracking communications and requests made by other Seleção members through their database access. The group discovers Seleção No. 2, Jintaro Tsuji, is manipulating public perception by marketing Takizawa as the "Air King" folk hero, aiming to cast him as either a martyr or terrorist. Eden also identifies efforts to alter Takizawa's public records, linking him to the deceased Prime Minister of Japan. Sis and Eden face direct threats when Seleção No. 1, Daiju Mononobe, launches a hacking attack on their systems, forcing a temporary Eden network shutdown to prevent further compromise. Later, Sis joins Micchon Katsuhara in hijacking one of Mononobe's mobile command centers, which houses a critical Juiz AI system component. This action supports Takizawa's strategy to confront Mononobe and address the escalating conflict among the remaining Seleção. Her activities maintain consistent involvement in Eden's technological and strategic operations throughout the narrative.