User blog comment:B214/General Discussion/@comment-24098614-20170718220315/@comment-10330822-20170724125220

The big problem was devils seem to have a hard time giving birth, so them recovering their numbers even after that long war is very difficult. Not to mention they value blood purity, which means there probably wasn't much mating for the sake of recovering numbers either. Its not like the Fallen Angels, who for all we know have a much easier time having children and don't descriminate amongst each other.