>>100173138>>100173201I would tell you to read the comic, but eh.
The Sentry, aka Robert Reynolds, is a reality warper. His backstory in the original 2000 run by Paul Jenkins was that he was Marvel's strongest hero (like Superman) but he was forgotten. The series spent the entire time bringing about his "return" and going into why he was betrayed
only to reveal he was forgotten because he had a split personality that was also the most dangerous supervillain in Marvel. The 2000 run was meant to be a one-off, but then Bendis brough the Sentry into "main" Marvel. So the 2005 Sentry run goes a bit more into it.. Basically Robert Reynolds was a teenager who wanted to get high, and for some fucking reason decides to get high on a random serum in a lab. One of the big things about the Sentry is schizophrenia and the uncertainty of the past - Bob is an unreliable narrator. Its why the panels always switches to different artstyles, as its meant to be a commentary of the Marvel's 616 canon, as well as how retcons keep happening all the fucking time.