Of Myth & Legend
Urban legend, stories, mythology. They are full of tales of creatures. Some look human and others are closer to an animal. Some are an admixture between both and others are something else completely.
Even in these modern times, we have The Jersey Devil, the Mothman, Sasquatch, the Yeti, the werewolf. Even in these times of Reason, there are hundreds - perhaps more - of perfectly normal people who have claimed to see things which neither they nor science can explain. Even country and culture has them and some of them bare a remarkable similarity to one another. Others are simply odd and quite terrifying.
Suffice it to say that not all of the nephilim Exiles are demi-gods, heroes and the stereotypical handsome or beautiful saviour of soon-to-be-sacrificed maidens and princesses. We suppose these heroes need things to fight which are terrifying and inhuman enough looking to add to their heroism. We suppose orcs, goblins, gremlins and trolls have to exist so that heroes can vanquish them and be proclaimed heroic.
We suppose that not all of the monstrous births from the early days of human/angel liaisons were exterminated and wiped out as Lucifer would like to claim, that they continue on, completely out of his control, breeding in the hidden and dark places of the Earth. Many were driven off and assumed dead. Once Atlantis was drowned that assumption was considered a guarantee. It seems to have been a false and misleading one.
Not every legend is a complete fabrication nor every myth an invention. They tell you that the monsters are not real. They lied.