New Avengers, Vol. 1 #9A (2005)

The Sentry, Part 3
The team works on the Sentry's psyche, helping to unlock his memories before the Void defeats them all. He unlocks enough of the memories to learn that people don't remember him because the Mastermind convinced him to use his powers to prevent them from remembering him, and the Sentry himself is also the Void, his greatest archnemesis.
Release Date: 2005