More than ten thousand years ago, long before the holy war had started, another realm of existence suffered a planet wide epidemic wiping out the entire male race. With only females in every land, birth is just a myth and offspring is created from magic.

After years of research and dedication, the royal sisters had finished a prototype spell. They would summon a male creature to restore this long lost gender. The spell would take a vessel that had genes most compatible for a mare. The major down side of the spell is that they didn't get to choose what was summoned. They were expecting humans, because they were the most compatible in the past, but what they didn't expect were demons. Two sons of the demon king Meliodas and Zeldris.

(Yes, I did ask persmision from the author to make this story.)