Cujo Winchester
Twins, there were twins, one had the fangs and ears, the other didn't.
Born with a faunus dad and a human mom these two Winchesters were born with a problematic mom, an absent father and a widening gyre between them.
Genlace they called it, a condition which makes an expected to be faunus into human genetics, thus making them human.
That made one a man and the other a dog.
Cardin and Cujo always got along though, Cardin waited all of his life to one day get his own pair of ears, but as life grew tougher and expectations dropped, Cardin's jealousy and any form of grief towards the faunus kind morphed into something.. different, rage and anger.
The idea of being a man along these creatures has done things to him, it's turned him into something different. He began to hate all faunus alike, he eventually ran away from home to live with anyone else.
Cujo had to be strong for his grieving mum, but she eventually couldn't handle it and passed away, Cujo had her cremated and hid her ashes in a cave somewhere.
Cujo would descend into alcoholism, soon he'd be full of rage too, he'd do things he'd never do, because he wasn't himself, he'd harm those around him, he'd harm who he'd consider his friends, he's run from authorities and killed the undeserving as his drunken stupor and other forms of bringing addiction there might be made him out of control, he couldn't control himself anymore.
All before he's even reached eighteen years of age.
He's heard of Beacon's destruction, that means his brother is on the run somewhere out there.
A shimmer of what he once was, a good hearted faunus boy who wanted the best for everyone, especially his brother who was getting all the more distant as the years had gone by.
That shimmer eventually gets drowned in substances. But when one drowns a light, the light keeps shining.
Just a short start for something