I have a cat named Stubborn that was skin and bones come in the house and just sit down in the living room like she owned the place. She's been here since.
I thought Stubs was a kitten, but in fact when I took her to the vet a few days later after she'd gotten a little stronger from simple food and water, the vet told me that she was actually 1-2 years old. Her growth was stunted, she was so malnourished. Now she's stuck the size of a kitten, but she's getting along pretty well now since we got rid of the bugs and she has food and water.
I think I know where she came from, and people in that particular neck of the woods don't tend to care about anything but themselves.