Thanos Kills Gamora
We learned back in Guardians of the Galaxy that Thanos considered Gamora to be his “favorite daughter,” but the film didn’t explore how deep their relationship went. In Infinity War, we discover that, though Gamora hates his guts, Thanos genuinely cares for his adoptive child. It’s proven by the fact that he’s able to get the Soul Stone.
On Volmir, Red Skull explains to Thanos that he can only claim the Soul Stone if he sacrifices the thing that he loves most in the universe. Gamora believes that the villain has lost, as he doesn’t love anything. Unfortunately for her, she’s wrong. Freely crying, Thanos decides that uniting the Infinity Stones is more important than Gamora’s life and throws her off the abyss.
As the first (but so far from the last) death of a hero in the movie, Gamora’s demise is truly shocking. Even more so than the loss of Heimdall and Loki, this proved that Infinity War was really going to do whatever was necessary to up the stakes and was willing to kill even the major protagonists of the franchise.
On a more character-based level, it also showed the single minded determination that drives Thanos. Even if he is human enough to love Gamora, his thirst to get all the Stones is enough to make him kill her. Kudos to both Josh Brolin and Zoe Saldana for making this scene so devastating to watch.