Shimura works as an officer at the General Information Desk in a facility processing the recently deceased. His duties involve guiding new arrivals through bureaucratic procedures to determine their afterlife destinations based on their lives and causes of death, including suicide, murder, accidents, and illness. He maintains a consistently polite yet detached demeanor, treating the deceased with feigned politeness and a professional smile that masks inner detachment. His behavior is monotonous and somewhat cynical beneath surface-level civility, stemming from significant unresolved trauma.

Shimura committed familicide in his past, murdering his family before ending his own life. This traumatic background fundamentally shapes his existence in the afterlife workplace, fueling his emotional guardedness and creating an aura of a dark person with mysterious and intense charm. His psychological state manifests through subtle cues, like a smile obscuring profound inner turmoil tied to his actions while alive.

He interacts professionally but with emotional distance toward colleagues such as Ishima of the Murder Division, Nishikawa of the Suicide Division, and Hayashi of the Accident Division. The deceased university student Miki Michiru, processed by the Accident Division, gradually becomes aware of aspects of his past through prolonged observation at the facility.

The narrative links Shimura’s unresolved trauma to his role in guiding others toward accepting their deaths. His journey explores whether confronting his past enables reconciliation with his actions and eventual peace. This trajectory remains incomplete across adapted media, as the source manga continues serialization beyond dramatic adaptations, leaving his ultimate resolution regarding his family’s fate unexplored in animated or live-action formats.