I introduced 2 kittens to my very spoilt and princessy tripod cat - keep them in separate rooms for a while, or use the cat carrier trick etc to get them used to each others smell - expect a lot of hissing, tails standing out like toilet brushes and a few swatted paws around the ears - but generally once that little storm's over they'll get on OK (until the kittens decide that the adult's swooshy tail is a great cat toy and then they'll get a paw around the ear as a general rule).
In my cat's case - she looked them up and down, hissed a bit, and then walked up to the meek and quiet one (the other's a right psycho case), and plonked her stump down on his back and used him as a leg rest! Quiet kitten and tripod got on really well - he'd "suckle" on the fur on her neck and they'd curl up together - she never got on as well with psycho kitten - but he hated everyone and was a nutcase (he's so nuts he hurls himself from a wall onto a first floor window ledge - and regularly misses and you see cats falling past the ground floor window if you're stood in the right room of the house).
The kittens now live with my mother as when I moved I was only allowed to have one cat in my new flat.
Currently having a lot of fun with the glass patio doors here - it's a very cat-heavy neighbourhood and we've got a couple of really curious ones who come into our back garden, right up to the door to see what those funny humans are up to - and it drives the tripod ballistic - she hisses, spits, tries to jump at them - they try to jump back so you end up with 2 cats just hurling themselves at a glass window for 10 minutes.
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