Paraphrased below from Marvel's own website:
Arriving at the Sanctuary through a wormhole caused by the fractured Bifrost, I met the Other, he was second in command and overruler of the ancient race of extraterrestrials known as the Chitauri, and then was Thanos. Self titled, supreme being, tyrannical child of Titan.
Offering me, the God of Mischief, dominion over my brother's favourite realm Midgard, or as you might know it as...Earth. Thanos only requested the Tesseract in return. And safe return of the sceptre.
Gifted with said Sceptre that acted as a mind control device, I would be able to influence others. Unbeknownst to me, the Scepter was also influencing me, fueling my hatred over my dull brother Thor and the unsuspecting inhabitants of Earth therewith..
Hey guess what?
I had been running with this theory in my roleplaying since 2018. In fact since 2016 when it first made an appearance in my crossover book on FanFiction.Net in 2016.