The title says it all

I have an Idea for an Undertale AU. And apparently, it's a good idea? So here, have a book. --- Long ago, two races ruled the earth. But when a plague of corruption swept through one species, causing a half of their population to attack the humans, the humans thought it safer to banish all the monsters underground. Now, the Underground is a Battleground. The battleground of the Pure and Corrupt armies. This Is UnderCorrupt. -- COMPLETED!

There was only one hybrid in the Pokemon world. She has the ability to change from an Alolan vulpix to a human with a fluffy white tail, fox ears, and her Pokemon moves And back. She continues to avoid humans and takes care of many vulpixes along with an Alolan ninetales. One day while protecting her mother, she was caught by a skeleton trainer. She kept her identity of a hybrid a secret and slowly trusted him. Now what?