Well I dont mean an ANGEL just an angel-like being. If a dark Elf sorceress can birth a Succubus, I dont see why a priestess couldn't birth like a Nephilim or something (half-angels from the bible).
Erevi birthed the Succubus when Nergal blessed the conception. The Succubus has the objective of getting pregnant by MC to bring forth Nergal's Champion (amore powerful demon spawn).
Ziva could birth a Nephilim/cherub who has a similar objective. Get preg with MC's child & bring forth Qetesh's Champion (a powerful angel spawn).
Just saying