7. Death
It’s impossible to guess whether or not Marvel choose to include Death in Avengers: Infinity War, but it would certainly be a fascinating way to delve into Thanos’ mind.
One of the most powerful beings in the Marvel Universe, Thanos is infatuated with her, an obsession which began when he was a young man and she first appeared to him. Is Death real or a figment of his insane mind? That perception has depended on the writer for the most part, but her role in the movies could be pivotal. She’s the one who convinces Thanos to use the Infinity Gauntlet in order to wipe out half of the universe (which Death claims will save it in the long run), but no matter what he does, he’s unable to win her love.
The fact that he smiled in that Avengers mid-credits scene at the mention of courting Death could be a very strong hint of what’s to come…
