Robert Downey Jr.'s Doctor Doom is after Franklin Richards for a major reason, and the new Fantastic Four member should be key to Avengers: Doomsday.

First Steps. In a mid-credits scene he was seen allowing Sue and Richard's son Franklin Richards touching his face. But what is the larger impact of this scene leading up to Avengers Doomsday?

In Marvel Comics, Doom’s fixation on Franklin is legendary. He views the boy’s near-limitless powers as the key to creating and ruling Battleworld, a twisted reality of his own making as seen in Secret Wars.