According to Marvel comics, Sentinels are a group of super-powered machines, designed to terminate mutants. As such, they majorly serve as antagonists to the X-Men across all formats. The Sentinels made their big-screen debut through 2014’s X-Men: Days of Future Past, which saw Peter Dinklage’s Bolivar Trask conceptualize their invention.

Robert Downey Jr. shared a new photo from the set of Avengers: Doomsday and gave a nod to Hawkeye’s Jeremy Renner. Downey will return to the Marvel Cinematic Universe as Doctor Doom and made a post on social media as he films the new movie.