10 MCU Plot Points Marvel Has Completely Abandoned

10. Samuel Sterns' Fate

The MCU has abandoned plenty of characters - Darcy Lewis, Jane Foster, Lady Sif - but Samuel Sterns' story is one of the more overlooked, exciting prospects the cinematic universe didn't fully exploit.

His first (and last) appearance was in 2008's The Incredible Hulk. Near the end of the film he's attacked by Emil Blonsky and suffers a cut to the head, with some of Bruce Banner's blood seeping into the wound. The wound starts to bubble and mutate, and as Sterns smiles at the camera, we leave him. Forever.

This moment was clearly planting the seeds of Stern's transformation into The Leader, a villain from the comics. The Leader has green skin and an oversized brain, so the shot of Sterns' forehead expanding was almost certainly put there on purpose.

In The Avengers prequel comic titled 'Fury's Big Week', Black Widow actually encounters Sterns, who now has increased mental capacity - but has also gone a little crazy. Sterns is taken in by SHIELD, to be studied by the organisation's scientists.

But hold on a second... SHIELD was disavowed after Captain America: The Winter Soldier, with remnants of the organisation eventually coming together a few years later. So what happened to Sterns? How could he still be held captive after SHIELD crumbled?

There could be a super-intelligent individual with a giant head just wandering around somewhere, and that's a weird thread to leave dangling.