When most people think of Norman Osborn, they think of the Green Goblin, one of Spider-Man’s all-time greatest foes. However, regular readers of Marvel Comics will know, as of late, Osborn has grown beyond the bounds of Spidey’s rogues’ gallery to become a true “big bad” of the Marvel Universe. It says a lot that, to many, the name “Norman Osborn” strikes more fear than “Green Goblin” ever did. Osborn has come a long way, but it seems the journey he needs to undergo to join the Marvel Cinematic Universe might be a long one. We've already seen Osborn appear in two Spider-Man franchises in the past two decades, but there are certainly crazier fan-theories out there, so anything is possible.
When Marvel Studios made a deal with Sony to use Spider-Man in the MCU, they didn't just obtain the rights to Spidey - they got all of his villains, too. The Vulture and The Shocker have already appeared in Spider-Man: Homecoming, so there’s no reason Osborn himself couldn’t appear in a sequel. Given his recent comic book history, it seems likely Spidey will find himself facing the man, rather than the Goblin, this time around.
By the time Marvel Comics began their Dark Reign event, Norman Osborn had reached a significantly higher station than “Spider-Man bad guy.” The former Green Goblin climbs the social ladder first as the leader of a government-sponsored team of ex-supervillains, The Thunderbolts, and then by proving crucial to Earth’s victory over the Skrulls in Secret Invasion. Osborn lands the killshot on the Skrull Queen, and suddenly he is thrust into a position of prominence as - with Nick Fury in hiding and Tony Stark disgraced - he’s named director of SHIELD, which he promptly renames “HAMMER.” With Stormin’ Norman running the most powerful organization in the world, the Dark Reign had only just begun.
Soon after taking the reigns of HAMMER, Norman Osborn forms his own team of Avengers, colloquially known as the Dark Avengers. Each of the members is a supervillain masquerading as a hero, including Bullseye as Hawkeye, Venom as Spider-Man, and Moonstone as Ms. Marvel. For his own heroic twist, Osborn paints a Captain America color scheme onto an old Iron Man suit, becoming the Iron Patriot. Publicly, Osborn and his Dark Avengers portray themselves as the “real heroes,” but behind the scenes they’re just as wicked as they were before.
Early on in his Dark Reign, Norman Osborn writes a list. On this list are a number of “problems” he would like taken care of, and most of these problems come in the form of various superheroes. Using his Dark Avengers and other less scrupulous characters, Osborn sets out to incapacitate, incarcerate, or even eliminate some of his most perplexing enemies. He is unable to get his hands on Spider-Man, but he does manage to imprison some prominent names, including Clint Barton. The most extreme result of “The List” is undoubtedly the brutal murder of Frank Castle, The Punisher, at the claws of Daken, son of Wolverine.
Osborn isn’t satisfied with simply forming his own dark versions of the Avengers, X-Men, and Thunderbolts. He also forms an evil version of the Illuminati, an organization started by Reed Richards, Tony Stark, and others to solve the ills of the Marvel Universes. Osborn’s Cabal, which includes members like Doctor Doom, Loki, and Emma Frost, has significantly less altruistic goals in mind - namely, how they can extend Osborn’s Dark Reign as long as possible and benefit from it without upsetting the delicate power structure he has created. Of course, villains of this caliber can only stomach one another for so long, and the Cabal inevitably breaks apart.