Who could Dwayne "The Rock" Johnson play in Deadpool 3 and the MCU?
Could he be the Villain of Deadpool 3?
If recent rumors serve to be correct then it would none it appears it will be none other than Dwayne "The Rock" Johnson. Rumors of Marvels attempts to cast Johnson have been going on for long over a year, and why not he's currently one of the top billed actors in Hollywood so its understandable as to why Marvel Studios is so desperate to get him under contract for some role, and assumingly any role he wants to portray. The question is what role? Well if we consider comic rival DC + Warner Brothers delayed Johnson's Black Adam movie indefinitely and maybe Marvel can fill that villain role he clearly is interested in portraying.
What about a character that could also reappear in the MCU outside of Deadpool movies? Wonder Man AKA Simon Williams is a character who first debuted in The Avengers #9 in 1964, and since he has toed the line between good and evil. He gains his powers from chemical and radiation treatments with "ionic" energy by the hand of Baron Zemo and has basically every power under the sun ranging from teleportation to energy to super strength and size manipulation. Simon Williams is also an exceptionally wealthy individual, he inherited his company from his father and is a successful movie star. Wonder Man/Simon Williams in the MCU which would make a great story as he tarnishes Deadpool's image as an Actor and as a villain. Wonder Man is an on and off again Avenger as well so you can still have Johnson continue the role in the MCU following Deadpool 3, potentially joining the Avengers?
Nathaniel Essex is one of the most deviant X-Men's villains known for his obsession with evolution and experimentation. Cloning? Splicing of DNA? Evolving the mutant race? Sinister is in his name and maybe these themes may be too dark for the MCU but not for a Rated R Deadpool movie. We had references to the Weapon X program but Sinister's experiments are on another level, and he is as formidable physically as he is strategic, not to mention his numerous clones. As exciting as it would be to see a legion of Johnson's Mister Sinister clones fighting Deadpool, its the least likely character he would play unless they have a grand plan for Sinister going forward in future X-Men franchises.
T-Ray (no other name that we know of) one way to pitch his origin story in the movie is that a mercenary named "Jack" shows up while T-Ray and his lover are on vacation. "Jack" betrays their trust and kills his lover Mercedes. T-Ray believes "Jack" then went on to become Deadpool to allude his enemies. Another more out there storyline, T-Ray Wilson and Mercedes Wilson finds a wounded man named "Jack" and brings him back to health just for him to turn on them killing Mercedes and stealing Wade Wilson's identity to hide from his former employer. T-Ray unable to cope with the loss of his wife begins to train and becomes Deadpool to avenge his wife, he then is taught magic and voodoo by Jack's former employers and becomes known as T-Ray. He pursues everyone's favorite Merc with a Mouth and tells him this story and Deadpool actually questions if he was "Jack" and especially considering how he lost Vanessa in the last film this could play out great bickering as to who is real Wade Wilson between Johnson and Reynolds.
A clone of cable and could fit perfect in the MCU especially when it would probably be Deadpool's fault for creating him. Stryfe has telepathy which could play great as Johnson intrudes upon Deadpool's 4th wall comments to the audience by talking over him and leaving the two bickering.
Stryfe also has telekinesis as well superhuman strength and durability so its not like Johnson needs to do much in regards to his physical appearance. Although in the MCU he'd have new breath of life into the character as he has been depicted as villainous madman to mutant supremacist in the comics.
Garrison Kane is a cyborg that was a former member of Cable's Mercenary team called the 6 Pack. He also has 4 cybernetics limbs after losing them in an accident and signs up for the Weapon X program.
The question for his usage in Deadpool 3 would be is he coming from the Future to get revenge on Cable for abandoning his mercenary team, assuming the other members died following Cable's departure to the past. Or he could appear in the film as an Agent for the Weapon X program trying to get revenge on Deadpool for when he blows up the compound in the first movie. perhaps Garrison Kane and his team were in the explosion when it happened killing all of them except Kane who is then given his cybernetic implants with a goal to kill Deadpool or kidnap him to replicate his healing. Kane could even be manipulated into being the villain by Weapon X program as they make an appearance in the MCU. By the end of the movie we would have enough character's for a X-Force movie, consisting of Deadpool, Domino, Cable, Kane and of course Peter!
Although we know Ryan Reynolds is desperate to get Hugh Jackman to return as Wolverine for a Deadpool movie but if Johnson appears in this film that would be just as satisfying.
Regardless of whomever Dwayne "The Rock" Johnson chooses to play in the MCU I am sure that Marvel Studios will try to maximize his potential in one or more MCU films. Whether that's a villain, an anti-hero or a new hero in the MCU (say perhaps Namor or even Dr. Doom?) He is one the top paid actors in Hollywood but Marvel would be smart to get him under contract for several movies because people will go see his movies regardless if they are an MCU fan or not.