The recollection of Adam revealed the appearance of a large, glowing, humanoid creature. He was discovered during the Katsuragi Expedition in the White Moon deep underneath Antarctica. They attempted to make contact using the Lance of Longinus, but ended up triggering the Second Impact as a consequence. This caused Adam's body to revert to a primordial state. His soul was later brought back into Kaworu Nagisa, with is physical remains being recovered and used to design all of the Evangelion units except for EVA 01.
Ryoji Kaji later brought Adam to NERV, where Gendo Ikari had him grafted into his right palm. In the End of Evangelion, Gendo Ikari attempted to fuse Rei Ayanami with Adam by forcing his palm into her body.
 Seed of Life
Adam technically isn't an Angel, but a Seed of Life. His type allows to him to create beings with unimaginable power and strength. He uses this ability to create the Angels encountered in the series, playing one of the biggest roles in the entire series by having an influence in nearly every aspect of the plot.
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