Robert Reynolds, most commonly known as Sentry, is a fictional character that appears in Marvel Comics. Sentry was created by Paul Jenkins , Jae Lee, and Rick Veitch and debuted in The Sentry #1 in 2000.  Sentry was created when he was accidentally exposed to the Golden Sentry Serum that granted him the powers of million of exploding suns. He is known to be among the most powerful Marvel characters and is notorious for his mental instability and connection to the dark manifestation of his powers, the Void.