After ingesting an experimental super-soldier formula, the lowly Robert Reynolds became the Sentry, one of the first and mightiest superheroes. He was trapped in a constant battle with his dark side known as the Void. After his membership with the Avengers, he joined Norman Osborn’s Dark Avengers and died after single-handedly destroying Asgard. More recently, the Sentry was resurrected by the Apocalypse Twins as one of their Horsemen, the Horseman of Death.