Constructed by Hiyori's father to console her after her grandmother's passing, Wasimo is a humanoid robot designed to replicate the grandmother's physical appearance, incorporating dentures as a distinctive feature. The robot exhibits unconventional movement capabilities—described as faster than a snail yet slower than a rhinoceros beetle, while paradoxically able to outrun bullet trains. Primarily existing within Hiyori's familial environment, Wasimo maintains relationships with her family members Masao, Papa, and Mama. Secondary connections include interactions with Dentures, Hajime, Tsune, Rinko, and community figures such as Catfish Beard Sensei, Murohashi Sensei, and a Lonely Terakawa.