Pietro Maximoff

If you didn't come out of the theatre wiping away tears after Age of Ultron, well, you didn't get into the movie enough. Go back and watch it again. I'll wait. Though Pietro was not a main character in the movie, he still sped his way into my heart before he even said his catchphrase. Which also happened to be his last words. There is no denying his death. He died. Past tense. But he will return at least by 2018, if not sooner.

        You know that Cradle? The one Helen Cho used to create Vision? She herself said that it creates new tissue and heals wounds. If Hawkeye could rush his body back to the Cradle fast enough, it could heal the bullet wounds. 

        Back to the catchphrase. "You didn't see that coming" are a few of the words the beautiful Russian says. And Marvel really takes these phrases seriously. Even when Infinity War Part 2 comes out, they'll still be making jokes about Cap saying "Language" at the beginning of the movie.  So it would totally be awesomely feelsy if he came back and had one more "You didn't see that coming" to start off the movie!
        Speaking of Cap, remember when he said if you get killed, walk it off? Foreshadowing! Joss Whedon honestly didn't need to put that in the movie unless he was foreshadowing future events.
Drowning in Feels,
Phoebe