Miyuki Serikawa resides in the same household as the central widow, appearing as a supporting character. She is one of the women featured alongside the widow and another woman named Chiyoko in explicit videos recorded by the widow's deceased husband. These videos, documenting sexual activities within an underground room, depict Miyuki participating in acts orchestrated by the brother. Within the narrative, Miyuki exists within a dynamic where the brother subjected the household women to ongoing sexual exploitation, cultivating their dependence on these encounters.

Positioned within the household's hidden activities, Miyuki's presence is defined by her connection to these recorded events and the household's secrets. Her background, personal history, motivations, and individual character development remain unexplored within the established narrative. Her ultimate fate and role beyond these events remain untold.