Comics' Greatest World: X (1994, Dark Horse)

Comics' Greatest World: X ran for 25 issues (1994–1996). Publishing format: was ongoing. The indicia title of the first issue is "Comics' Greatest World: X," and for the rest of the series it is only "X." X's first appearance is in Dark Horse Comics #8. X is a costumed superhero, non-powered except for rapid healing and a possibly alien nature. He's kind of like Batman without the moral center; he fights his city's corrupt power structure, but for his own reasons. He also kills quite often.