Mister X

A ruthless presence who sliced into Marvel's Modern Age with his debut in Wolverine #159 back in 2001, Mister X has carved out a reputation as one of the more dangerous and enigmatic figures in the publisher's darker corners. Created by Frank Tieri and Sean Chen, he's a character who feels right at home amid morally complex company — sharing pages with the likes of Ghost, Paladin, Frank Simpson, and Eric O'Grady across titles like Thunderbolts, Wolverine, and Secret Warriors. That's a notably gritty roster of collaborators, and it speaks to exactly the kind of shadowy, high-stakes world Mister X inhabits. With over two decades of appearances stretching from 2001 to 2024, he's proven himself a quietly enduring figure worth tracking down for fans who like their Marvel stories with an edge.