Akihito Narihisago is a male character standing 178 cm (approximately 5'10") tall, with green eyes and somewhat long, spiky, dull pink hair, paired with a small goatee. His current attire consists of a Kura prisoner’s uniform, including white bottoms, a black shirt, and a white jacket tied around his waist. A white bracelet is worn on his right wrist. Before imprisonment, he was clean-shaven with brighter, more upright hair, typically dressed in a black suit, a white shirt with the top button undone, and a loose black, white, and brown striped tie.

Akihito Narihisago, also referred to as Sakaido, is a former homicide detective who later became a Mizuhanome pilot for the Kura organization. He was once married to Ayako and had a daughter named Muku. Two years before the current events, Muku was murdered by a serial killer known as the Challenger. Ayako subsequently died by suicide due to grief. In retaliation, Narihisago killed the Challenger and was imprisoned as a result. During incarceration, he was recruited by Kura to use the Mizuhanome system, entering the minds of serial killers under the alias Sakaido to investigate and solve their crimes.

Operating as Sakaido, Narihisago displays a calm and proactive demeanor, demonstrating strong composure and a highly analytical, methodical approach to investigations. He exhibits empathy, often viewing those involved in cases as individuals rather than mere pieces of evidence. This is reflected in his willingness to prioritize saving lives over solving mysteries, such as delaying the resolution of Kaeru’s death to protect others. Despite enduring significant personal trauma, he remains driven by a deep-seated commitment to justice and a persistent motivation to save people.