that's why i'm thinking lamia. same biologically (roughly) but no blessing of the moon for those psychic powers. and considering the huntress seems bound to lose her blessing if vaginal sex is had... it just makes sense to me.
the witch however, i don't know. so you might be right about her making naga.
as for offspring kobold horde leaders, you might be right.
i just realized something, issa might be born from an elf that lost her protection... or maybe a nun that was granted blessings of the moon. (refer to dialogue with the infernals when giving up issa as an offering)
so that could mean the nun or the huntress could give birth to a smarter kobold than normal, or maybe another kobold variant.
edit: oi i said could, not preferable... but with that said, i don't think there's any issue with the nun birthing smarter kobolds.
Nah, just doesn't sound good. Feels like you're trying too hard to come up with a reason it could happen for it to be good for a plot point.(also, pretty sure the issa/moon magic thing is about the magic poured into him to alter his physical and mental states to what he is now, could be wrong though)
