Just a friendly reminder, your comment is considered as racist and could be flagged by mods. As for the manhua, it's probably a guilty pleasure for a majority. Seeing as it is translated(probably), people outside the Wall are interested too. Although the concept of dream conception isn't entirely original; as it has been seen in quite a few mythologies.
Apparently the dad just took the baby out of the mother. In fact, it's all on the father side that did the deed and make the baby. Mother is simply just in name.
could it be that the mother's daughter is actually a backup for the mother since the dad is an immortal maybe she's also an immortal? something like a clone maybe?