Hmm... I'm kind of ambivalent towards this. In one hand, I love it for your Sesshomaru voice in some parts, however, there are things that annoy me as well.

The ICness was almost there. So close and yet, with some parts - to me at least - it didn't sound Sesshomaru like at all. For example:

"With that one, I had to wonder if the defiance came from bravery or stupidity, for she seemed to be under the impression that no matter what she did, I would not harm her." - That was incredibly Sesshomaru. I read it and was wowed. Because it is what Sesshomary would think. He is Lord. He is Sesshomaru. No one should dare to defy him, let alone a weak human girl. I could see him tip his head back and stare down his nose at her. Awesome, that was simply awesome. 

However, the lovey-dovey bit at the end. I'm a romantic at heart, but I can't see Sesshomaru admitting to caring or not deserving someone. I've already said it but, he is Lord. It made me cringe; Sesshomaru's kindness and Inuyasha's submissiveness. I don't like it, it's not them in my eyes.

Your writing was very, very good. You had some lovely descriptions in there. "The wind shifted suddenly, sweeping my long hair away from my face and bringing several new scents to my nose." was one of them. I love the image of Sesshomaru with his hair splayed out behind him like a cape. It's so pretty! A big thumbs up for including such imagery! 

Just a quick suggestion though: Add a little paragraph or two in the beginning explaining where Sesshomaru is. I got to the aforementioned bit and went: "Oh... So he's not lying in bed, unable to sleep." XD I'm strange, I know. Anyway...

Overall, I think I liked it. I'm not completely sure; I love the beginning up until when the demon was slayed, but then it swayed. Keep working on it. In terms of ICness, you've gotten about a 6/7 out of 10. Writing, 8/10. I can see the improvement from when I first reviewed one of your stories! Now... Let's see what else you've got around here.