The Marvel Cinematic Unverse's Avengers: Endgame introduced a bevy of villains to fill out Thanos' army for the final act, including the re-introduction of the Chitauri warriors from 2012's The Avengers, but concept art reveals a new threat never seen before in the MCU movie timeline. In Endgame, the Avengers and their allies from all across the universe assemble in order to battle against Thanos' massive army. Though it's ultimately Iron Man who wins the day, it's not before plenty of fighting occurs.
