X-Man is also a comic book published by Marvel Comics Group. The artists involved in the creation of X-Man #1 were Jeph Loeb and Steve Skroce. A mint condition X-Man #1 can be had for maybe $15 CDN; the comic's hit on a lot of fame, though. I think it's a worthy addition to any collection.
X-Man, or Nate Grey, is a mutant (like the X-Men) with the powers of telekinesis and telepathy, so strong are they that they are slowly destroying Nate. The actual story behind why Nate is alive is a bit confusing, as Marvel tried to really mix up their stories, with the Age of Apocalypse and the Coming of Onslaught. So, I'll try to get it as right as I can. The mutant known as Cable was born in the future, in the Age of Apocalypse. In an alternate timeline, there were several events that were missing, allowing for Cable's birth, namely, the inclusion of Nathaniel Essex (Mr. Sinister) in Scott Summers' (Cyclops) and Jean Grey's lives. When you boil down the storyline, it turns out that Nate Grey is Cable again, but from an alternate timeline. Nate was genetically engineered by Essex.
A battle with the mutant called Holocaust sent Nate to our world, in great comic book story style. They've thrown in a lot of interesting backstory with the X-Man, for example:
Cable has a "technovirus", which I won't go into for the sake of ease (but think "borg" just the same). X-Man didn't come from that timeline, where he was infected with the technovirus. Cable has to use his own fairly incredibly telekinetic gifts to hold that virus in check. Nate's a teenager with little experience in the world, and he doesn't know much about his mutant powers; Combine that with the fact that he rhas something of a short temper, and you've got a pretty explosive guy.
In the aftermath of the horrible Onslaught comics, this is a good survivor. It's a fun read, and after the first few comics, it's no longer weird. Nate gets himself a love interest, and still blows a lot of shit up. Fun. But alas, not everything is forever, as X-Man knew, because of a failsafe Essex had placed in his mind, that he would die by age twenty-one. X-Man killed himself, spreading his essence to all living things. Now, who said comic books can't be touching?
As an aside, I feel it necessary to point you to fellow comic book nutcase atesh's writeup entitled "The Age of Apocalypse". You may end up more confused about Marvel timelines and all that, but it's interesting, insomuch that it attempts to explain a few things about the whole Nate Grey/Cable/Apocalypse thing.