It seems as if Orochimaru and Sasuke both have their secrets, and reasons for keeping them. Orochimaru for instance has yet to reveal(to at least the reader) his true reasons for leaving and what happened to his original body. No one remembers this but Oro let Naruto live during the chuunin exams because he didn't want to interfere with the plans of the atatsuki. This action is later contradicted during the Sannin fight. He view's naruto's growth as a threat, and opts to kill him on the spot. At the time, Naruto's growth and ability seemed to really scare Orochimaru. Now he's using Naruto's growth to thin the ranks of the Atatsuki for him. It makes you wonder what Oro's true goal is about. Sasuke seems to also be keeping a secret. He knows who Madara Uchiha is and now he know kyuubi. I believe that Sasuke has asked Orochimaru more to understand Naruto. That is why Sasuke is truly able to surpress kyuubi. I'm sure he got as much information as he could on both the Seal and how to use he sharingan to view into Naruto's mind. I don't think Sasuke was ever dishonest with Orochimaru about his goals and probaly made this clear. I also believe that Orochimaru now has no choice but to fight Itachi because Sasuke's soul will never rest until he has completed his goal. This plays into the past where Oro gave the person who was his current body, one wish that he would grant. Oro already knows Sasuke's one wish. So he must do everything to grant it or the body take over will be compromised. Another secret Sasuke has is the true nature of the sharingan. He has seemed to take his own sharingan to a completly different level. If and when these two merge, I believe all secrets will be out in the open. It still leaves the question: What are they both hiding? Any thoughts?