Meow. :3 Kitty is a cat because of course she is. Then Johnny needed to be a cat because black cats symbolically represent bad luck!! Also, making him a black (unlucky) cat was a great way to merge him with his shadow. That is also why he has a little fang. Cats are one of the few species that I’ve assigned more than one character to (it’s just these two, though. There will be no more cats).