The long-rumored Thunderbolts has reportedly entered into “very early development” at Marvel Studios, according to MCU Cosmic. It remains unclear if the project is being developed as a film or a live-action series planned for the Disney+ streaming service, where Marvel Studios will debut multiple miniseries acting as an extension of the theatrically released Marvel Cinematic Universe. Also unclear is when Thunderbolts is slated to premiere or which characters might be involved. Thunderbolts could be readied for Marvel’s Phase 5 — already shaping up to include Black Panther 2, Ant-Man 3, Blade, Captain Marvel 2 and Spider-Man 3 — as president Kevin Feige has mapped out the MCU’s future through 2024.

In the Marvel Comics, the Thunderbolts are a team of supervillains-turned-heroes. Baron Zemo, a longtime enemy of Captain America and the Avengers, reunited villain group Masters of Evil when Earth’s mightiest heroes appeared to perish against new threat Onslaught. The costumed villains then posed as a new generation of crime-fighters in the absence of the real superheroes, with some ultimately emerging as reformed do-gooders when masquerading as heroes for their own gain.

Like the Avengers, which has had a revolving roster, past iterations of the Thunderbolts included Spider-Man enemies Norman Osborn and Venom, Daredevil enemy Bullseye, Taskmaster, the Eric O'Grady Ant-Man, the Punisher, the Red Hulk and Deadpool.

There has been speculation The Incredible Hulk and Captain America: Civil War star William Hurt, who next reprises his role as Thaddeus “Thunderbolt” Ross in Black Widow, could appear in Thunderbolts. Beyond Helmut Zemo (Daniel Brühl) — who next returns to menace Falcon (Anthony Mackie) and Bucky Barnes (Sebastian Stan) in The Falcon and the Winter Soldier — other still-surviving MCU foes with the potential to reappear include Justin Hammer (Sam Rockwell), Abomination (Tim Roth), Ghost (Hannah John-Kamen), Sonny Burch (Walter Goggins), Shocker (Bokeem Woodbine) and Vulture (Michael Keaton).

“We debated what we should announce today. ‘Should we announce Phase Four and Five?’” Feige told MTV News in July. “We’ve planned them out, we’ve got five years down the road and I was like, I think 11 projects in two years is plenty having not mentioned anything for two or three years.”

Upcoming Marvel Studios projects include Black Widow on May 1, 2020, The Falcon and The Winter Soldier in Fall 2020, The Eternals on November 6, 2020, Shang-Chi and the Legend of the Ten Rings on February 12, 2021, WandaVision in Spring 2021, Loki in Spring 2021, Doctor Strange in the Multiverse of Madness on May 7, 2021, Spider-Man 3 on July 16, 2021, What If…? in Summer 2021, Hawkeye in Fall 2021, and Thor: Love and Thunder on November 5, 2021, and Black Panther 2 on May 6, 2022. Marvel Studios Disney+ series without release dates include Ms. Marvel, Moon Knight and She-Hulk.