Adam, the First Angel is now available for free download at the Webdude's site. All of the other Angels descended from Adam, they possess the "Fruit of Life," the source of the Angels' power and immortality (also known as the S² Engine). As you can clearly see, Adam's body was used as the basis for the Evangelions. Also, Adam is named after the first human created by God in the Book of Genesis.
Adam - [Download Page]