Ario, a larval ant, is the son of Yoshiki Arito and Helen, completing their ant family dwelling underground near Milk Chan's house. His life revolves around the escalating marital conflict between his parents. As Yoshiki's suspicions of Helen's infidelity intensify, he frequently confronts her directly. During these disputes, Helen often deflects or redirects Yoshiki's attention towards Ario. Though consistently present amidst this domestic tension, Ario remains a passive observer, never actively engaging in the arguments. The situation deteriorates until Helen departs, taking Ario with her. This separation culminates in Yoshiki writing a final letter to his family and committing suicide in the series' concluding episode. Primarily serving as a narrative element within his parents' storyline, Ario witnesses their discord and separation without significant individual development or action beyond his role as their child.