Thanos wiped out half of all living beings throughout the universe. And, all it took was a snap of his fingers, and people ceased to exist. He called this a move of mercy, as all these deaths were instant and painless. But before the Snap, Thanos had to achieve his goal the hard way. He went from planet to planet and caused mass genocide.
His own planet perished as it ran out of resources. So, he made it his goal to save other planets from themselves. But killing people planet by planet was too slow. So, he found a better way to execute his universal plan at once. Still, before grabbing the Infinity Stones, he killed several races of beings in the cosmos. Here’s every confirmed race Thanos killed before his Infinity War snap:
Thanos adopted Gamora from the Zen-Whoberi planet. Before that, he executed half of the Zehoberie people. According to him, the rest of the Zehoberei people lived with abundant resources. But, her title card in Guardians revealed that she was the last survivor of her race. So maybe Thanos’ plan did not work after all. Or this could be a minor MCU plot hole.
The Nova Corps. already had a tough time when Ronan attacked. A good chunk of their fleet was wiped out. But four years later, Thanos attacked the planet to get the Power Stone. It’s unclear whether he killed half of the Xandarians, or all of them. We’ll probably find out about that when Nova steps into the MCU.
After getting his hands on the Power Stone, Thanos attacked the Asgardian vessel to get the Tesseract. When we got his first glimpse in Infinity War, he and the Black Order had already killed half of the Asgardians on the ship. And then, he dusted even more Asgardians when he snapped his fingers. No wonder Thor felt like a failure. He lost more than anyone could imagine.
Avengers: Endgame revealed that Thanos and his minions killed several people on Korbin. If you’re confused about them, then let me remind you that this was the planet where Gamora made her first appearance in Endgame. This is also the planet that Beta Ray Bill belongs to. We didn’t necessarily get to see Thanos kill any Korbinites. But he was wiping blood off of his blade. So, it’s safe to assume that he did murder a bunch of Korbinintes. I guess Beta Ray Bill would remind us of this when he arrives.
Thanos may not have stepped foot on planet Kylos directly. But he did send Ronan to kill off Drax’s people. This was a part of Thanos’ mission to bring balance to the Universe. We don’t know a lot about Kylosians. According to Drax, Ronan slew both his wife and his daughter. But rumors suggest that we’ll see Drax’s daughter Moondragon in Guardians of the Galaxy Vol. 3. So, we might get to explore Drax’s past through her. I’d love it if Ronan shows up for a flashback sequence on Kylos.
Thanos kept the Dwarves on Nidavellir hostage until Eitri designed his gauntlet. And then, he killed them all anyway. That was just brutal. Thanos proved that he was a man of his word when Doctor Strange asked him to spare Tony’s life. So, it’s quite surprising to know that he killed all the dwarves even after he got what he wanted. We’ve seen that the two Thanos in Endgame and Infinity War were different. The younger one was more brutal and villainous. So maybe that’s why he killed the dwarves.
There are plenty of other planets that Thanos must have visited. So, we’d like to see which other races Thanos wiped out in the past. Maybe the Eternals franchise could shine some light on that.