TV-Series
Description
Rinko Koujiro, a petite young woman with short, straight black hair, is a scientist and former colleague of Kayaba Akihiko. She studied Electrical and Electronic Engineering at the Toto Institute of Technology in Japan, working in the Shigemura Lab. Koujiro first met Kayaba at age eighteen during her initial college year. She later contributed to developing Sword Art Online, unaware of Kayaba's intentions for the game's deadly incident.
During the SAO incident, Koujiro deduced Kayaba's location at a hidden mountain cottage. Though intending to confront him, she instead assisted in maintaining his physical condition throughout his extended dive. After the incident concluded, Kayaba implanted a fake long-distance micro bomb near her sternum to create the appearance of coercion. Koujiro regarded this as the only gift Kayaba ever gave her. Authorities arrested her post-incident, but she was later released on bail and acquitted.
Approximately two years after the SAO incident, Koujiro relocated to San Francisco, California. Her scientific expertise includes research at the California Institute of Technology and developing the Medicuboid medical device using data Kayaba left behind. In March 2025, Kazuto Kirigaya contacted her via email, leading to a Tokyo coffee shop meeting. Koujiro declined Seijirou Kikuoka's invitation for confidential FullDive research. However, on July 1, 2026, she received an email from Yuuki Asuna detailing Kirigaya's situation. Agreeing to assist, she informed Kikuoka of her acceptance. On July 5, 2026, she traveled with Asuna—disguised as her assistant "Mayumi Reynolds"—to Rath's Ocean Turtle facility. There, Koujiro witnessed Rath's Soul Translator research and learned the circumstances of Kirigaya's presence.
Her personality demonstrates loyalty and sustained caregiving, evidenced by her support for Kayaba during his dive despite his actions. She maintained these feelings throughout their association.
During the SAO incident, Koujiro deduced Kayaba's location at a hidden mountain cottage. Though intending to confront him, she instead assisted in maintaining his physical condition throughout his extended dive. After the incident concluded, Kayaba implanted a fake long-distance micro bomb near her sternum to create the appearance of coercion. Koujiro regarded this as the only gift Kayaba ever gave her. Authorities arrested her post-incident, but she was later released on bail and acquitted.
Approximately two years after the SAO incident, Koujiro relocated to San Francisco, California. Her scientific expertise includes research at the California Institute of Technology and developing the Medicuboid medical device using data Kayaba left behind. In March 2025, Kazuto Kirigaya contacted her via email, leading to a Tokyo coffee shop meeting. Koujiro declined Seijirou Kikuoka's invitation for confidential FullDive research. However, on July 1, 2026, she received an email from Yuuki Asuna detailing Kirigaya's situation. Agreeing to assist, she informed Kikuoka of her acceptance. On July 5, 2026, she traveled with Asuna—disguised as her assistant "Mayumi Reynolds"—to Rath's Ocean Turtle facility. There, Koujiro witnessed Rath's Soul Translator research and learned the circumstances of Kirigaya's presence.
Her personality demonstrates loyalty and sustained caregiving, evidenced by her support for Kayaba during his dive despite his actions. She maintained these feelings throughout their association.