Rei Ayanami is a fictional character from the Neon Genesis Evangelion franchise, created by Gainax studio. In the anime series of the same name, Rei is an introverted girl chosen as the pilot of a giant mecha named Evangelion Unit 00. At the beginning of the series, Rei is an enigmatic figure whose unusual behavior astonishes her peers. As the series progresses, she becomes more involved with the people around her, particularly her classmate and fellow Eva pilot, Shinji Ikari. Rei appears in the franchise's animated feature films and related media, video games, the original net animation Petit Eva: Evangelion@School, the Rebuild of Evangelion films, and the manga adaptation by Yoshiyuki Sadamoto.

Yoshiyuki Sadamoto is a Japanese character designer, manga artist, and one of the founding members of the Gainax anime studio.