Originally posted by Kutulu
Both Hulk and Sentry share similar mindsets in that their minds are fractured with multiple personality disorder. Basically without their superpowers they would both be in insane asylums. Robert had his mind fractured into Void and Sentry (evil / good), and Hulk had his mind fractured into Hulk and Banner (savage / scientist-logic). So it's not really secret identities in the same way that Superman has - with Superman, he's always Superman, he was born that way and will stay that way, whereas both Bruce and Robert become something else that lies deep within their minds.
But if the only split in Sentry's mind is Sentry/Void then Robert and Sentry are the same persona (ie not Void).