fighting or playing

three days ago we got a ten week old siamese female kitten. when we brought her in my 2 year old siamese male (who is her brother) was hissing his head off as expected. we let the girl get settled into one room and later that day put her in the carrier to let Neko sniff her and stuff. well he hissed and hissed and eventually just sat there moaning. well yesterday we had Neko and the kitten in the kitchen and let the kitten run around (with water bottle near by) and Neko got in hunting mode with huge pupils and ran up to her and sniffed her. they would chase each other and ocasionly he would go over her and bite her neck. today i let the kitten have the run of the house and they seem to be ok most of the time but i'm not sure if they are playing or fighting, this is how it goes: The kitten will prance over to Neko and start to rub him, then Neko put one of his front legs over her and flips her onto her back and then dives on her. He does not scratch but he bites over and over. she does manage to hold Neko's head and kick him. Neko will pull back and she will stay on her back but reach at his face and slap him gentlybut he will dive on her hard and start biting and kicking her. she kicks two but eventually she starts to meow. I can't tell if she's meowing cause it hurts or cause she just feels like meowing (and she loves to meow.) there's no screaming or hissing but he bites her neck and it seems like he could easily kill her if that's what he wants. Neko's ears are slightly back and his pupils are fully dialated but his fur is flat and there are no wounds or flying fur. we seperate them at night or when we can't watch them. another thing is Neko won't let the kitten rub him or show affection Neko will start beating her up. they do play chase with kitten chasing Neko and vice versa but the neck biting kicking hold down and flipping over on the floor is worrying me.so please tell me if it's play, fighting or dominance hierarchy stuff. Thanks!

Is Necko neutered, because if not, you could end up with all kinds of trouble even besides what you have now.

Looks like playing to me. But Neko's neck biting seems like a male's sexual aggression.

yeah Neko is neutered and once Lily (the kitten) turns 6 months she'll be spayed. They are doing better this morning and Neko is grooming her.

im jelous, i want my 10 week old and my 2 year old (both females) to get along. They are much better then they were 4 weeks ago. My cat too acts almost like she is hunting the kitten at times.She chases her around and swats at her , but then sometimes they will just be sitting there, and my cat will start hissing and then attack the kitten and try to bite her neck. I too am nto sure when it is aggresion and when it is play.