Mario Abe is a 29-year-old uniformed police officer in the Tokyo Metropolitan Police Department's Criminal Investigation Bureau, primarily assigned to clerical duties. His responsibilities include managing and organizing records, filing materials, and maintaining documentation within departmental reference rooms or archives.

During an incident in the archives beneath government buildings, Abe was filing documents alongside colleagues Inspector Maruoka and Officer Satomi Kaizuka. When unexplained tremors rattled the facility, Satomi initially attributed them to an earthquake, but Abe, drawing on practical experience, questioned this assessment. The group then encountered a giant salamander creature, causing significant alarm among the personnel. This event occurred during his routine departmental operations.