Iwao Nishina is a character created specifically for the live-action film adaptations, making his first appearance as the commander of the Kanto Library Base with the rank of Special Library Superintendent. He is a survivor of a traumatic event known as the "Hino Nightmare," a past catastrophe that deeply affected the Library Force's history and left Nishina with severe physical injuries. As a result, he uses a prosthetic leg, which makes mobility difficult and confines him to a wheelchair.

In the story, Nishina's role is that of a high-ranking authority figure within the Library Defense Force. His background as a survivor of the Hino Nightmare informs his understanding of the ongoing conflict between the Library Force and the Media Betterment Committee. The plot of "Book of Memories" involves Nishina being abducted, along with the main character Iku Kasahara, by a group that supports the Media Reconciliation Act, an event that becomes a central crisis. The Library Force is able to locate and rescue them by utilizing a GPS tracker hidden inside his prosthetic leg.

Regarding his personality and personal motivations, detailed information is not available. Similarly, his key relationships with other characters beyond his formal position as commander, his personal development throughout the story, and any notable special abilities are not documented. The character exists as an original creation for the live-action narrative.