The Angel Ending is an Ending in Prisoners of the Elder One. It occurs after accepting the halo from The Elder One. Please see the entry on the Sorceress Ending for information on how to face the Elder One.
When Erik enters the Elder One's room, the God fucks him in the ass, turning him into a pallid woman, before taking her virginity. She accepts the halo, fully swearing her soul to her new Master, and becomes a new Angel, though she occasionally feels a strange sadness for her former sister.