Make a very mean cat more lovable?

My cat is a little over a year old. And he's really mean. He claws and bites for no reason. And waits around corners to latch on to people's legs. He was sorta mean when he was a baby. When I'd try to sleep, he'd grab on to my hand and start attacking it. He's lovable sometimes. Once in a while I can pick him up and he'll sleep on my shoulder. Or he'll jump on my chest and sleep when I'm going to bed. But that's about it. He also tries to hump my arm everyday. Which bothers me. And he's really vicious about it. I have claw marks all over my arm. I don't know what to do with him. Help. D:

First, have him neutered if he's not. That will cut out any sexually based aggression. He needs to learn that this kind of playing won't be tolerated. Walk away and ignore him when he does it. That will teach him that attacking ends playtime and he gets no interaction with you. Make sure to have plenty of fun things for him to do. Cardboard boxes and paper sacks to jump in and out of are great fun for cats. Use the sticks with feathers on the end to play with so your hands are further out of reach for him to grab. Here's an article on play aggression which will probably shed some light on things for you.
http://www.sniksnak.com/cathealth/aggres...

Hello, I wonder how you brought this cat up given that your name is Devilish! If you are calm and loving to the cat he will respond likewise given time.

He is only a year old and not yet neutered which would account for some of his aggressive behavior. Getting him neutered will calm him down a lot and sounds essential here.

There is nothing you can do about it except love him more
this is how his brain works, he hates people, and attacks you, but when he sees it is you, he loves you
i guess it is since he was a kitten an experience with people made him like that