What is Evangelion anyway?
Evangelion(Or "Eva" in short) are humanoid "robots" designed to fight against mysterious conquerors "Shito" (or "Angels"). They can generate its own AT field, and can carry weapons which "neutralize" the AT field of Angels. However, they are extremely costly to build and maintain. Also, they are cumbersome to operate. It needs external power units in order to fight for a long time. Without extrenal power source, it can operate maximum 5 minutes without turning on AT field.
Three Eva units were ever in service in NERV Headquarters, Eva-00, Eva-01
and Eva-02. There's an extra one EVA-03 being tested in Japan, but it
went wrong during testing in episode 18, and was destroyed by Eva-01.
Please select the one you want to get more details. Thank you.