10 Unused X-Men Villains MCU Phase 4 Could Introduce
2. X-cutioner
Who? Carl Denti is a former FBI agent. He has no powers, but utilizes multiple forms of technology to fight mutants. While his cause may seem just, X-cutioner will stop at nothing short of murdering any mutant that has killed a normal human, but he'll also take out anyone who gets in his way.
In the comics he's stolen the tech he uses from many alien races and sometimes teams up with the good guys.
How he fits in the MCU: We've already seen how the government/SHIELD has been storing weapons and technology from the various enemies in the MCU when Tony Stark and Steve Rogers figured it out in Avengers. Here we'll have FBI Agent Carl Denti investigating murders that are suspected to have a connection to the rise of the "mutant phenomenon" that has been emerging since "the blip".
He stumbles across some atrocity committed by a yet-to-be-known mutant baddie. He's seen enough and he steals the technology he needs from government storage and goes on a rampage. Not knowing who to direct his rage towards, he gets revenge on any mutant he deems a threat.