Formally known as Multipurpose Humanoid Decisive Weapon Synthetic Lifeform Evangelion, the Evangelion Units were constructed over the course of fourteen years as a result of research conducted by Gehirn. Construction costs for a single unit are said to be astronomical, and their official U.N. sanctioned purpose is to protect mankind from the Angels.
The Evangelion Units are not the stereotypical combat robots found in most other mecha shows. In fact, as the series progresses, it becomes evident that the Evangelion Units are not machines at all, but bio-mechanical constructs (synthetic life forms). Although lacking a will of their own, the Evangelion Units are essentially humans in the form of Angels, and can be considered living entities in the service of NERV.
Evangelion Units 00-04 are assigned under the command of NERV Headquarters located beneath New Tokyo-3 in Japan, which also guards Adam, Lilith, and the Lance of Longinus (key components of the Human Instrumentality Project).
The Evangelion Units are said to be the only weapons capable of defeating the Angels. This is primarily due to their unique ability to generate and neutralize AT Fields. Despite their awesome power as weapons however, they are limited to pilots born just following the Second Impact (fourteen-year-old children).
Operating on electricity, the Evangelion Units rely on external power supplied via Umbilical Cables, which are connected to power sockets located in designated Armament Buildings scattered throughout New Tokyo-3.
Mass-production Evangelion Units
The name Evangelion is derived from 'Eva', German for Eve, the wife of Adam in the Old Testament, and 'Evangel', the English term for gospel.