Seventh Part of the Seal
Which developed over years in a number of games and books.
We're pretty much in the same place with the Nephilim as we were with the Kilrathi after WC1. Just because they look somewhat insect based doesn't make them a mindless horde. Even from what little we know, they have different castes and roles and culture that we've only seen the beginnings of.
I have to agree with Ried, you can't really make decisions based on what little information we have. Like the Kilrathi, we really didn't have much info on them after the first game. To think of it, we really didn't have much info on the Kilrathi until well after WC2 when the books started coming out.