The Avengers is great and all, but it definitely leaves a lot unexplained as to how Loki came to be allied with Thanos and lead his Chitauri army in an invasion of Earth. The last time we saw him in Thor, he wasn’t quite so world-conqueringly villainous and clearly hadn’t had any contact with the Mad Titan at that point. So what happened in the interim?
Fans have been coming up with theories about it for years and a big one is that Loki’s sharp change in personality was caused by the Mind Stone housed in his scepter, lent to him by Thanos to aid his hunt for the Tesseract (the Space Stone) on Earth. Well, now Marvel.com has confirmed that this is indeed the case. During a fascinating piece which runs through the history of the God of Mischief in the MCU, the website wrote:
“Arriving at the Sanctuary through a wormhole caused by the Bifrost, Loki met the Other, ruler of the ancient race of extraterrestrials the Chitauri, and Thanos. Offering the God of Mischief dominion over his brother’s favorite realm Earth, Thanos requested the Tesseract in return. Gifted with a Scepter that acted as a mind control device, Loki would be able to influence others. Unbeknownst to him, the Scepter was also influencing him, fueling his hatred over his brother Thor and the inhabitants of Earth.”
Clearly, it didn’t take much persuasion for Loki to join Thanos’ side in order to take over Earth to get his own back on his brother Thor. However, the Mind Stone definitely exacerbated his thirst for vengeance, hatred and probably his ruthlessness as well. In his three other appearances in the Thor movies, he’s much more of an anti-hero – a man with not too many scruples, but not totally evil. So, this confirmation makes a lot of sense.
It could also explain another plot hole from The Avengers. It always seemed kind of dumb that Thanos gave up his only Infinity Stone in order to get a second and ended up losing both of them. Now we can infer that he had to give Loki the Mind Stone so that it’d fuel his anger and make him a more useful tool.
Of course, once he was free of Thanos’ control, Loki eventually turned against him and stood alongside his brother in Avengers: Infinity War. It seemed to cost him his life, too, but we know he’ll be back in his very own show on Disney Plus, so not to worry.