I'm guessing it's the bit about no other animals that the problem here as most everyone here has other kitties, dogs, rabbits, hamsters, elephants, ferrets, rats etc
I hope this little lady soon finds her happy forever home.
Is there any chance with careful treatment to regain her trust and a very slow introduction to another cat that she might come around? I obviously have no idea what happened to poor Shadow in the past, so I might be asking a stupid question.