This was very interesting and well written! _ I always wondered what Kabuto was thinking at the moment. I think you captured his feeling perfectly! :D This part was my favorite:

But there were times where just had to tell himself, “As soon as Sasuke is dead, you can take over Orochimaru-sama. To help you was my only purpose in life. I’m not going to change that now.”

beautiful. good job.

I liked this story, loyalty and hate mixed beautifully to create an air of extreme sadness; the last paragraph made my already damp eyes water until I actually cried. I will definitely add this to my favourites. Well done.