Nebula

If the way Thanos ends up being defeated in the Infinity War movies reflects how he was defeated in the Infinity Gauntlet comic book arc, it may just be a case of Nebula stealing the gauntlet off him and undoing everything he had done with it.

This would be even more fitting in the Marvel Cinematic Universe than it was in the comic books, because Karen Gillan’s version of the character is the Mad Titan’s adoptive daughter – and she resents him because of his favouritism towards Gamora.

It would be the ultimate revenge for Nebula’s treatment at Thanos’ hands if she was to thwart his attempts at taking over the universe – not only fixing everything, but also undoing the scars she had gained working for her adoptive father.

In the comic book arc, this scenario ultimately resulted in Adam Warlock taking the Infinity Gauntlet from Nebula and discovering Thanos working humbly on a farm. Who knows if that would be the case in the MCU?