Warning! This article contains spoilers for The Fantastic Four: First Steps. Thanks to The Fantastic Four: First Steps, I am convinced that Doctor Doom will be Avengers: Doomsday's main character. The ending of The Fantastic Four: First Stepsdid not do much to actively set up Avengers: Doomsday,

Here's who that mysterious figure was in the credits scene of "The Fantastic Four: First Steps" and how it sets up Doomsday.