I think a lot of this comes from some of the lore that's only given in supplementary material like games and the like.The angels are children of Adam just like Humans and all other lifeforms on earth are children of Lilith. While each angel may be itself a unique species, they all come from the same...

Also requesting access to edit the wiki largely to fix grammatical mistakes I see (I've seen some in some of the Angel wiki pages.) Big fan of Eva and this site is a great resource, so I'd like to see it as good as it can be