introducting a new kitten.

Question
QUESTION: i recently got a cat last month, it followed me home and i took care of it its name is king, and now just 3 days ago me and my girlfriend were walking and w saw a kitten, dirty and alone under a car in the rain. and it  was meowing for help, i was outside a while and no one claimed it, so i took it home.
King didn't seem too shocked about this , i think it' because he was an outside stray anyway, he is used to other cats.
King always keeps an eye on the new one, named Rong Rong
rong rong  i read is in teh juvenile stage of life where he play with everything and wants contact with king. King doesn't like this contact. He doesn't hiss or meow. I have seen him licking rong rong a few times, But it's a lick lick lick BITE THE BACK OF HIS NECK!!!!!
he never continues to lick him, then rong rong meows and king lets go, Repeat.
We tried the Isolation, But isolation is literally impossible, Because my house has sliding doors that don't lock and king found out how to open the doors, He always opens them and comes in and sits close to rong rong watching him and then he bites again.

The cats don't hiss, it looks violent but sometimes rong rong purs the whole time too.  we want to quarentine them but it's probably not going to happen, How long do you think Rong rong will be bullied? will king kill him?
i am afraid to sleep because i don't want king to hunt rong rong in his sleep.

ANSWER: Daniel,

I wanted to ask a couple of questions to get a better idea of what we're dealing with so that I can help you more effectively.

Is King neutered?

How old is Rong Rong?

---------- FOLLOW-UP ----------

QUESTION: no king isn't neutered. he just had a problem with his tail *when we found him his tail was mauled by another cat*it's been a month his tail is much better now, But the doctor said we should still wait a little for any emotional stress to clear up before we make him neutered.

king and rong rong were both strays adopted from outside, the doctor suspected king is about 1 year old give or take, and rong rong hasn't been to a doctor yet, he is by guess is maybe 1.5-2 months, his head is about the size of a chicken egg. and his fur is just fluff rather then hair.

Answer
Daniel,

It's important to keep a very close eye on King, intact male cats can sometimes kill young kittens - it's a way to ensure that their mother will come back into season more quickly so they can mate with her. Rough play from King towards Rong Rong shouldn't be permitted at all. You can use humane disciplinary tools like a squirt bottle filled with water or a can of compressed air to stop things from getting out of hand. The squirt bottle must be brand new - recycling bottles that contained cleaning products is quite dangerous for cats. If you use a can of compressed air to get things to cool down it's important that you never point the can directly at the cats, these products tend to contain chemicals that can cause frost bite and other painful injuries so if this is what you'd like to use you can only point it in the general direction of the cats, but keep it well away from them. Most cats don't like to be sprayed with water, it means that they have to work hard to clean themselves and get dry. The cans of compressed air work well because there's a hissing sound emitted when the trigger is pressed and cats immediately get the point because they understand what a hiss means.