It took a decent length of time before Humans had started to manifest from their absorbing of all of the Cursed and Blessed energy that came pouring from Heaven and Hell.
As anyone could imagine, taking in power from Hell would turn someone into a rather devilish form, and the same goes for the Angels and those affected by their powers.
Cursed humans would begin to sprout horns in many shapes and sizes, or even long flowing golden hair. The creativity of the random nature of Heaven and Hell played as it liked with Human's bodies.
Humans before the War struggled as they did with their differences as it was… this layer wasn't needed, but it's here now.