Thanos is the main antagonist of the Marvel Cinematic Universe film series, as an antagonist of Marvel's The Avengers and Guardians of the Galaxy, and the main antagonist of Avengers: Infinity War and its untitled sequel. He is a powerful alien warlord who rules over a dead dimension and commands a massive army known as the Chitauri. He allied himself with Loki to invade Earth, and allied with Ronan the Accuser to destroy Xandar, both in exchange for the deliverance of two powerful Infinity gems, but they both failed to accomplish this task and had betrayed him.