The Avengers is basically the origin story of a group of superheroes. The tesseract, a powerful cube containing the space stone (one of the six infinity stones ), has been stolen from S.H.I.E.L.D. by Loki, an Asgardian god and the brother of Thor. The Avengers are a team of superheroes in the Marvel Universe. Despite starting in its own corner of the Universe, it expanded over time and has, since its creation, featured a large number of characters in a variety of combinations. Characters in bold are currently active on the main team or on the West Coast.