Long ago, two races evolved. One of which was the Humans, and the other were the Kemonomimi. While the Humans broke away from their animal-counterparts, Kemonomimi used their genetics to their advantage. They broke away from Human civilization, until one group finally wanted to explore the world.
Thus birthed the Ame no Hikari, a group of brave and courageous Kemonomimi. They have abandoned their animal traits, and now strive alongside the human realm.