Can I Save My Cats?

My boyfriend and I have been in a relationship a little over three years and we live together. As of a few months ago he's developed violence tendencies. He's gotten violent with me pretty frequently, I live with constant fear and anxiety. Things would be a lot easier to end if we didn't have cat babies. I've always wanted to have a pet and he decided we should get two kittens. They are my absolute LIFE. They have brought me out of so many depressing episodes and really just make me happy to be alive. When we adopted them though, he filled out the paperwork and purposely left my name out of the adoption papers so I couldn't leave him and take the kittens too. I've paid for everything regarding the cats, food, litter, toys and all furniture they have. I'm always the one to feed them and just care for them in general. If I left and took the cats, would that put me in any legal issues? I'm sure that if he's ballsy enough to hurt me, he'd hurt them too. Last time I tried to leave, he ended up getting super aggressive and wouldn't let me get anywhere near the cats, saying that if I leave him, he's putting them up for adoption. What should I do?