[ForlornHope]

I don't think Sesshomaru will turn on Rin. I think it's more likely that he'll leave Rin somewhere to be with other humans than kill her.

Firstly, Sesshomaru is too noble for such a betrayal. He wouldn't "turn on" someone, especially one of his servants.

Secondly, he's not one to needlessly slaughter humans. Granted, he has killed his fair share of humans, it was always because they opposed him in some way (i.e. they'd try to pick a fight with him or he'd tell them to move out of his way and they wouldn't).

Thirdly, I believe he does care about Rin, like a person cares for a puppy (I don't think his hatred of humans would ever allow him to care for Rin as anything that would put her on the same level as him, like a daughter or anything of that sort). Thus, when he can't take her with him anymore, he won't to kill her, but he'll give her to someone else to take care of and be done with it all.