Biblical: Armisael is supposed to be called on to assist in childbirth. The Talmund says that a woman could ease childbirth by reciting Psalm 20 nine times, but if this didn't work (or the woman couldn't remember all of Psalm 20), then one is to seek Armisael's help next by invoking him.
Evangelion: Armisael appears as a giant hovering double-helix, like DNA. It then shifts into a solid strand, and strikes Unit 00 in the stomach. It starts to force itself in throughout all its blood vessels and causes Rei to go into a hallucination where she speaks with the Angel. The Angel, in the shape of Rei, offers to join bodies with her, and Rei--in a bid to define herself as her own person--turns the Angel away. In the director's cut, Unit 00's back explodes into the shape of all the Angels up to Armisael in one big clump. Then, it pulls back in and Rei self-destructs Unit 00, taking the Angel with her.