The latest trailer for Marvel's "Thunderbolts*" sets up a grand, thrilling stand-off. The titular group of antiheroes — comprising Yelena Belova (Florence Pugh) and Red Guardian (David Harbour), among others — are seen fighting a supervillain who taunts their incompetence. "You thought you were going to be some great saviors? You can't even save yourselves," this figure declares, making it amply clear that the Thunderbolts might not be equipped to deal with such a formidable threat. This threat in question is Robert "Bob" Reynolds/Sentry (Lewis Pullman), whose villainous turn is prompted when he is contaminated by The Void, which turns him into a dangerous force of nature known as Dark Sentry. But who exactly is Robert, and how did such a promising hero morph into a nightmarish entity?

Before we dive into Dark Sentry's origins, it is crucial to understand the sociopolitical context of the world that requires the Thunderbolts to step in.