Loving and Hating a Cat

So, this is Tumnus.  Mr. Tumnus.  He was the bookstore cat until one too many incidents with claws and teeth led me to decide he was better off away from the public.

He's overweight, and ill-tempered.  Sometimes, like in this picture, he's docile and very cute.  You know, like when he's sleeping.  But when he's awake his number one goal is food.  And for some reason that makes him...just really nasty.  You bend down to pet him and he exposes his belly and then...swipes at you.  He sniffs the air and you give him a hand to smell to test the waters and he bites.  Really bites, like that "chomp and hold" kind of bite. 

I have three other cats, Hazelnut, Maggie, and Emmy.  They're not perfect, but they're generally really pleasant, and pretty clear about boundaries and when they want affection and don't.  Tumnus, though -- he's a liar.  He'll purr and lay down in front of you and when you go to reach out your hand he pounces.  It's not playful.  As soon as you get near him, he flips over back onto his stomach like you just jabbed him with a hot poker. 

Tumnus is dealing with permanently damaged kidneys from an undiagnosed bladder infection.  I adopted him from the Animal Rescue League in August of 2012 and he always used the litter box and never showed signs of discomfort.  But all this time, or at least for a lot of it, the bacteria in his body was eating away at the lining of his kidneys.  Now, I know cats are good at hiding their feelings and especially good at hiding pain.  But -- really?  No sign at all?

So it's easy, nay preferable, to try to chalk his nastiness up to him being in pain.  He was much calmer and less liable to snap when he was on his drugs, certainly.  But I'm worried he's just miserable.  Just a big jerk cat.  I mean, there's no law that says every cat has to be either wonderful or misunderstood.  He doesn't like our other cats, he picks fights, he pees on the carpet in a very territorial manner.  I'm worried he's just a big, nasty cat who doesn't want to have anything to do with us.

He likes Dallas better than me, which is fine, as I have (as I said) THREE other cats.  But, like all masochists, I want the cat to like me.  Hell, I want the cat to LOVE me.  There's no reason he shouldn't.  I feed him and change his litter and try to give him love.  Scritches and brushes and belly rubs.  But he lashes out and it gets old real quick.

So I'm trapped between love and hate.  He's just a cat, right, and the "judgement" of me as unworthy by him shouldn't mean anything.  But it does, and so I'm stuck in the in-between.