Evangelion Unit-00, also known as EVA-00, is a prototype Evangelion unit in Shin Seiki Evangelion. It is one of NERV’s giant biomechanical weapons used to fight the mysterious Angels threatening humanity. Piloted primarily by Rei Ayanami in early appearances, EVA-00 is notable for its unstable early design, distinctive blue-and-yellow color scheme, and experimental nature. As a prototype, it plays an important role in revealing the technological and psychological complexities behind the Evangelion project.