Quote Originally Posted by krazyaboutkatz
Congrats on your new kitty!!! He sounds adorable and I can't wait to see some pictures of him.

The best way to introduce a cat to another cat or even a dog is to do it as slowly as possible. Hissing and growling is normal and will hopefully go away in time. You can also use a towel and rub the kitten with one and your other cat with another one and then let each cat smell the towels so they get used to each others scent. Some people have even dabbed a little bit of vanilla on each cats head or neck so that they'd smell alike and this is supposed to help. Usually kittens don't pose as too much of a threat to the older cats so they are accepted much faster and easier. Good luck and please keep us updated about them.

Some people, me included, have just let the kittens run loose with the other cats and let the cats work things out. I think this works best if the other cats are used to living with other cats.
Thanks for the advice! I actually think having to quarantine him in the bathroom is a good thing...he can get used to the sounds of the household before anything else. I will try rubbing a towel on him & Seine. I won't be able to introduce them for at least 2 or 3 more days, but hopefully it goes ok!