10 Movie Heroes Forced To Kill For The Greater Good
2. Scarlet Witch Kills Her Love - Avengers: Infinity War
Poor Scarlet Witch has had a tough ride in the MCU. Borne out of a tragedy when her parents were slain in warfare, she was then experimented on (admittedly willingly) by HYDRA, saw her brother killed, accidentally killed hundreds of people in Africa and then had to fight her robo-boyfriend and unwittingly distracted him so much he crippled their other friend. A poor innings, to say the least.
And then to top it all off in Infinity War, that same lover, Vision, asked her to destroy him to stop Thanos from getting his hands on the Mind Stone, as she was the only one capable of doing so. Despite initially arguing against it, when the time came, she was forced to put her feelings aside and kill Vision for the good of the universe. You can practically feel her anguish as his life slips away under her powers.
In the end, it doesn't even matter, since Thanos reverses time and undoes her sacrifice anyway to kill Vision again. But the thought was there.