Sewashi appears in the Dorami-chan film series as a resident of the 22nd century and a consistent member of Dorami's friend group from that era. He participates in group activities and adventures alongside Dorami and their companions.

He features among the cast in "Dorami-chan: Wow, The Kid Gang of Bandits!", involved in the events of that film. Sewashi also appears in "Dorami-chan: Hello, Dynosis Kids!!", accompanying Dorami and friends on a time-travel expedition to the prehistoric past with the purpose of scientific verification related to dinosaur evolution.

His character functions within narratives focused on group adventures, often involving time travel or other extraordinary situations. Sewashi's base setting remains the 22nd century when not engaged in these activities.