Captain America: Brave New World – The comic history of The Leader, the mysterious Gamma-powered mastermind hiding in the shadows

A new clip from Captain America: Brave New World is giving fans our first, very, very shadowy glimpse of Tim Blake Nelson's return as Samuel Sterns in his guise as the Gamma-mutated villain the Leader, along with a mysterious monologue voiced by the actor, who is back in the MCU for the first time since 2008's The Incredible Hulk.

That film, one of the MCU's earliest entries, has been largely left behind. But the return of Samuel Sterns as the Leader finally makes good on a cliffhanger that's been bedeviling audiences for 16 years.

And while we don't know much about exactly how the Leader fits into the film just yet, aside from his obvious role as a villain, the character's comic book history is a matter of record that goes all the way back to the Silver Age of the '60s and the early days of the Marvel Universe.

Who is the Leader?

First appearing in 1964's Tales to Astonish #62 by Stan Lee and Steve Ditko, the Leader started life as mild-mannered Samuel Sterns, an overnight custodian in a chemical plant, who was of average intelligence and little motivation – until an accidental exposure to Gamma radiation changed his ordinary body and mind into something much, much more.

Like Bruce Banner before him, Sterns was transformed by the Gamma radiation, though where Banner's great intellect transformed into the Hulk's brute strength, Stern's mind was elevated to a point of supreme, insatiable intelligence. His body transformed along with his mind, taking on the familiar green hue of Gamma radiation, while his cranium grew to an enormous size to accommodate his now-massive brain.

Calling himself "the Leader," Sterns created a ring of spies and secret agents all dedicated to taking over the world and installing him as, well, The Leader. Sterns' Gamma-powered nature meant that he and Bruce Banner quickly gained each others' attention – and the pair's inherent Brains vs. Brawn nature quickly drew them into a decades-long arch-rivalry that continues to this day.

Over the years, the Leader and Hulk have clashed countless times, with the Leader often changing and evolving his Gamma-powered form, like Bruce Banner. At one point, after helping create the Red Hulk, Sterns even took the form of the Red Leader.

More recently, Sterns launched his most diabolical plan to destroy the Hulk yet, unlocking the metaphysical power of Gamma radiation and mastering control of life and death itself in the title The Immortal Hulk.

The Leader in the MCU

Though the Leader hasn't technically made his MCU debut just yet, Samuel Sterns definitely has. Tim Blake Nelson first appeared as a scientist working to help find a cure for Bruce Banner's Hulk transformation in 2008's The Incredible Hulk. Sterns makes a Gamma infusion based on Banner's blood that gives its subjects unstable Gamma powers – which he eventually uses to turn Emil Blonsky into the Abomination.

In the aftermath of Blonsky's transformation, some of the Gamma-irradiated blood seeps into a gash on Sterns' forehead, causing the start of an apparent transformation into the Leader for just a couple of frames … but he hasn't been seen since, with the film never receiving a sequel.

Still, the Hulk has definitely been present in the MCU since his one solo film in the shared universe, and his mythos has expanded with the Disney Plus streaming series She-Hulk: Attorney at Law, which even featured the return of The Incredible Hulk's Abomination, played once again by Tim Roth.

There were even some potential hints in that show that the Leader could appear or be behind some of She-Hulk's mysteries, but that connection never materialized, and it was announced a short time later that the Leader's return was indeed happening, but in Captain America: Brave New World.

This makes a bit of sense, considering President Thaddeus "Thunderbolt" Ross (played in Brave New World by Harrison Ford) will be transforming into the Red Hulk in the film. In comics, the Leader is partially responsible for Ross becoming the Red Hulk, working alongside MODOK and other villains to engineer his transformation.

Now, we're waiting to see exactly how Sterns' transformation into the Leader will look, but we've at least had a few sparingly obscure glimpses of what's to come. The suspense seems to be working, as the obfuscation of Sterns' mutated appearance seems to be building a new buzz around the villain.

We'll have to wait and see what he looks like, and how he fits into Captain America: Brave New World when the film releases on February 14.

For more, check our guides to upcoming Marvel movies and Marvel Phase 5.