Quote Originally Posted by Death BOO Z View Post
or maybe he and Kabuto know each other because Kabuto was his 'student' during the time he was a spy? that doesn't sound likely to me, seeing as Kabuto's entire team were spies, and that's not something you can hide from the teacher. Perhaps it's going to be revealed that Aoba is person who took in Kabuto as an orphan spy?

I'm guessing hokage personal guard. or something, maybe also a former super anbu.
He was probably ANBU. He sat in on the meeting of Jounin about Orochimaru during the Chuunin exam break.

http://manga.animea.net/naruto-chapter-93-page-7.html