Ai Natsuki  

, 夏木 あい

Natsuki Rin (sister) Natsuki Yu (twins brother) Sibling pair Ai and Yu are the younger siblings of Natsuki Rin and her twin brother Yu, respectively. Although they can be mischievous and cause trouble for their older sister, they are typical curious children who enjoy exploring new things. Despite being a source of frustration for Rin, the twins share a strong bond with their big sister, who will do everything in her power to protect them. Ai and Yu also get along well with Nozomi, despite occasionally annoying her due to their childishness and shared relationship with Rin as siblings.