I believe mother is a manifestation of the void or nothingness. the infernal god, or the sun, was born from the void, and dragons are children of the sun, thus the dragon is the child of mother's child.
1. My belief is that the mixing of infernal and divine essence essentially "destroy" each other, leaving some amount of void, and the void that is "created" with a dragon's cum in an elf's womb, is powerful enough to either take on a life of its own, or forcefully inseminates one of the elf's eggs and attaches to it, thus nagas are more aligned with the void than the sun or moon, explaining mother's interest in malice. otherwise, I'm not completely sure, trying to understand mother's dream scenes hurts my brain
3. its been a while since I've last played, so there is probably a fair amount of new content involving mother that I haven't seen yet, including this scene, so I can't be entirely sure