MCU: 10 Comic Book Characters That Could Be Introduced In Deadpool 3
2. Sinister
Since his debut, Mister Sinister has proven to be among the X-Men's most dangerous adversaries. Through his cloning experiments, the master geneticist has made enough spare bodies of himself to ensure he's pretty much immortal. He's also taken genetic samples of many superpowered beings, meaning he can create clones of almost anyone, and turn them into his henchmen. Because he has more powers than you shake a stick at, it would be foolish to underestimate the maniacal scientist.
Not only is Sinister's appearance in Deadpool 3 a no-brainer, he should serve as the film's main antagonist. Sinister has fought Wolverine for decades, making him one of his most recurring foes. He has faced Deadpool and Cable on many occasions - he even babysat Cable for a while when he was transformed into a toddler.
But above all else, Sinister needs to be in Deadpool 3 because he was supposed to appear in an X-Men movie ages ago! The insidious doctor was referenced in X-Men: Apocalypse and The New Mutants, and yet, the bugger still hasn't appeared in live-action. You can’t tease one of the Marvel's biggest supervillains twice without a pay-off (unless you're 20th Century Fox).