Who Kills Thanos? - Predicting Avengers: Infinity War's Climax

7. Loki

Though he was excellent in Thor: Ragnarok, the one frustration about Tom Hiddelston's Loki is that he seems to be doomed to perpetually live the same loop of betraying his brother, redeeming himself and then reverting to type again. And while that was slightly annoying in Ragnarok, it may just serve a foreshadowing purpose.

As the first trailer suggested, now that Loki has the Tesseract, he hands it over to Thanos - and rumour has it becomes an advisor to him - mostly through a lack of other choices. He is a master of self-preservation, after all.

But Loki does have some goodness to him and the fact that he ended Ragnarok as a hero was designed to remind us of that, so we don't write him off as a pure villain again just yet. He's too complex for that to be how his arc will go, and it wouldn't be out of the realms of possibility for him to turn on Thanos once more while there's a chance of victory (as Mephisto did in the original comics) and stick the killer blow.