Deadpool & Wolverine went through quite a few different iterations after first being announced as Deadpool 3 and we've known for a while now that at least one of them involved Mephisto.
We're not sure how the story was going to play out, though it sounds like the movie was set to visit Hell in place of The Void. Talking to The Hollywood Reporter, writers Paul Wernick and Rhett Reese explained that one early idea saw Wade Wilson battling an army of the undead in place of the Deadpool Corps after the Merc had escaped eternal damnation.
"We do know that Ryan wanted [Madonna's 'Like A Prayer'] to be in the movie from the very early stages, long before Hugh was involved, long before there even was a movie to put it in," Wernick started. "He was wanting to do a sequence of Deadpool in a oner, a move from left to right across camera, slicing up bad guys to 'Like a Prayer.'"
"Before it was Deadpool Corps, it was zombies. When Ryan jumped on the phone with us...he pitched this idea of Deadpool versus Zombies, and he pitched this final scene, the climax of the movie being Deadpool, going down the line and to Madonna’s 'Like a Prayer' and wantonly killing zombies. And we were like, 'Oh, that’s f***ing badass. That’s cool.' It ultimately evolved into the Deadpool Corps as we went along."
Reese added, "Yeah, there was an intermediate version where he was fighting his way out of hell, and those were demons, and he was cutting his way through demons. It was definitely a tentpole that we just kept holding onto."
Piecing everything together with other information recently shared about the threequel, it seems Deadpool was going to have to fight his way out of Hell, with Mephisto serving as the threequel's big bad. That presumably means there were no TVA or Multiversal elements and that the cameos may have been because those heroes had died.
For all we know, the Merc with the Mouth was going to also save Wolverine from Hell following his demise in 2017's Logan, pulling inspiration from Jason Aaron's "Wolverine Goes to Hell" story arc.
Elsewhere in the interview, the Deadpool & Wolverine scribes were asked about those rumours about Daniel Radcliffe playing a Wolverine Variant.
"No, I don’t think that ever came up," Reese confirmed. "It was a rumor that flew all over, but I don’t think Daniel Radcliffe was ever considered. I think I saw Danny DeVito rumor too. That was never considered, I don’t think."
Wernick responded, "No little Wolvie, we had pitched the idea of Danny DeVito."
"Oh, Danny DeVito, I guess that’s right. It was pitched, yeah," Reese acknowledged. "And ultimately it was thought it was just funnier to see Hugh. A short version of Hugh was funnier."
It's always fun to learn what might have been and Mephisto, an army of zombies, and Danny DeVito would have no doubt made this a vastly different movie!
Deadpool & Wolverine is now playing in theaters.