As well as bringing Sam Wilson’s Captain America to the big screen for the first time, Captain America: Brave New World’s cast features the returns of several past MCU characters. Among them, General Ross, recast for Harrison Ford following the tragic passing of William Hurt, Liv Tyler’s Betty Ross, and Tim Blake Nelson’s Samuel Sterns will be returning. Samuel Sterns was last seen being exposed to Bruce Banner’s gamma-irradiated blood, beginning his transformation into the Marvel Comics villain, the Leader. While the Leader will surely pose a huge threat to Captain America in Brave New World, the villain may have a secret weapon that could be even more dangerous.

The Leader Still Has Hulk’s Blood From The Incredible Hulk

Throughout The Incredible Hulk, Edward Norton’s Bruce Banner was in contact with a mysterious “Mr. Blue” in the United States, who had been helping the future Avenger try and find a cure for the Hulk. At some point, this mission took a promising turn, and Mr. Blue, a.k.a. Samuel Sterns, seemed to successfully remove the Hulk from Banner’s body, having carried out numerous tests on blood samples that Banner had sent. However, Banner hadn’t sent Sterns enough blood, so the scientist synthesized gallons of copies of Banner’s blood, which he stored in his laboratory in Harlem, New York City, all of which contained the same gamma properties as the original.

Since Sterns hasn’t been seen or mentioned since The Incredible Hulk, the status of these blood stores have also been forgotten. However, with Sterns’ return as the Leader in Captain America: Brave New World, it may be confirmed that the villain still has access to all of this blood. It was Banner’s blood that allowed Sterns to transform into the super-genius Leader in the first place, so it’s unlikely he’d want to part with his prized possession, but the existence of gallons of the Hulk’s irradiated blood could prove remarkably dangerous for Sam Wilson’s Captain America, and could set up some huge villains for many heroes in the MCU’s future.

The Leader Can Create An Army Of Hulks In Captain America 4

According to a theory shared by Reddit user Smrtguy85, the Leader’s access to Bruce Banner’s gamma-irradiated blood could grant him the ability to create new Hulks in the MCU’s Phase 5. The theory notes that, since the blood that the Leader has access to has been synthesized, and isn’t the original, these new Hulks may only have their abilities temporarily. However, it’s perhaps more likely that this won’t be taken into account at all, particularly since the Leader himself was exposed to some of this blood, and his transformation is presumably permanent. Even so, Sterns’ own transformation into the Leader could hint at some interesting storylines unfolding.

The gamma radiation transformed both Bruce Banner and Emil Blonsky into hulking monsters, but exposure to Banner’s blood has been shown to have different effects on different individuals. Jennifer Walters became She-Hulk after being exposed to her cousin’s blood, but She-Hulk is far less aggressive, dissociative, and looks much more human than the Hulk or the Abomination. Sterns’ transformation into the Leader seemed to focus primarily on his mental capacity, so it seems as though, should the Leader use Banner’s blood to create new villains, these foes could have a range of impressive abilities that may not resemble those of Bruce Banner at all.

The Leader May Create Another Powerful Hulk In The MCU

As well as potentially creating an army of Hulk-like villains in Captain America: Brave New World, the Leader could also use Bruce Banner’s contaminated blood to mark the MCU debut of another highly-anticipated Marvel Comics character. Since being introduced in The Incredible Hulk, many have been wondering when (or if) General Ross would become the Red Hulk, following his Marvel Comics storyline. Although this progression hasn’t been confirmed, there are suspicions that Ross could make this transformation in Captain America: Brave New World, and the Leader’s access to Banner’s blood provides the perfect explanation for this change, as he could create the ultimate weapon to battle Captain America and the Hulk.

General Ross made his first appearance as Red Hulk in Marvel Comics’ Hulk (Vol. 2) #1 in 2008, and was designed to be an uninhibited and tactically intelligent adversary to Bruce Banner’s Hulk, though his human identity was kept hidden until 2010’s World War Hulks storyline.