WARNING: The following contains spoilers for Avengers #48, on sale now from Marvel Comics.
Just when Jennifer Walters began to regain control of her faculties as She-Hulk, the Russian superhero team the Winter Guard kidnapped her and subjected her to cruel experiments in the Red Room. Transformed into the crimson, towering Winter Hulk, She-Hulk has become the ultimate killing machine and now stands fully unleashed upon the Marvel Universe. And right from She-Hulk's opening rampage against those that wronged her and those unfortunate enough to stand in her way, Jen reveals just how powerful she has become as the strongest She-Hulk has ever been.
After the Avengers launch an ultimately unsuccessful raid on the Red Room to rescue She-Hulk from the Winter Guard before it's too late, She-Hulk burst out into the wilds of Siberia after crushing any of the Winter Guard that tried to rein her in. She-Hulk's first order of business was to track down Gorilla-Man, the simian superhero that betrayed the Avengers to the Winter Guard and went into hiding to escape the heroes' wrath. As the Winter Hulk tracks Gorilla-Man down, the patrons of the dive bar he's taken refuge in attempt to stop her. They soon learn that this new incarnation of She-Hulk can not only smash with the best of them but that she now possesses the ability to breathe a green fire and incinerate anything caught in its maelstrom. And in Avengers #48 by Jason Aaron, Javier Garron, David Curiel and VC's Cory Petit, some of Jen's ordeal in the Red Room is horrifically revealed.
In addition to the physical and psychological torture and experimentation that the Red Room subjected She-Hulk to while she was imprisoned, the Russian government cut an illicit deal with the newly created vampire nation-state in Chernobyl. This led to vampires feeding on Jennifer Walters to help break her down physically and mentally while Dracula got to keep She-Hulk's radiated blood for his own nefarious purposes. This may have contributed to She-Hulk's transformation into the Winter Hulk becoming much more uncontrollable and violent, a symptom of the vampires' natural penchant for violence and bloodlust as the Red Room broke down and rebuilt its own She-Hulk.
In addition to the random goons defending Gorilla-Man, the Winter Hulk has put her new abilities to the test while on the high seas as she escorts her primate prisoner to justice. Interrupting this cruise is an army of Atlanteans. The Winter Hulk easily makes the waters run red with their blood as she withstands the intense pressures of the ocean's depths. And with She-Hulk by the far the most savage she has ever been, the Winter Hulk may be beyond the Avengers' help.
The Avengers first convened in a misunderstanding while facing the Hulk in an incident orchestrated by Loki. Years later, the Avengers must scramble to stop another rogue Hulk, this time with the transformed She-Hulk now cutting a path of destruction across the Marvel Universe. Exhibiting powers that she has never possessed before, She-Hulk's transformation makes her one of the most unstoppable figures on Earth. And if the Winter Hulk's rout of the Atlanteans is any indicator, Earth's Mightiest Heroes might not stand a chance against their old teammate.