Xorn and Magento are NOT the same person. Not if you read Excalibur #2.
Must... destroy.... Marvel....
But before I do, a little bio on Xorn for Slimjim (you're a sidekick because you have posted X posts, when you post more posts your subnick changes, I was a sidekick too):
In Grant Morrison's New X-Men run (beginning in #114 I think), a giant Sentinel is sent by Cassandra Nova to attack Genosha. When it gets there it almost completely wipes out every mutant on the island. One of the casualties is Magneto. He's in his tower, in a wheel chair (he's not well) and the tower is blown up by the Sentinel during its rampage.
Much later, in Hong Kong, the X-Men are investigating Jonny Sublime, the leader of the U-Men, who are humans that desire to become mutants and so they hunt down mutants, kill them, and graft parts of their bodies onto their own. Sublime is attempting to get a hold of a mutant named Xorn, who is held in a huge prison by the Chinese. Xorn would've been the next Buddha, but he has a star for a brain, so he was locked up by the Chinese, with a skull-shaped metal helmet on his head. The U-Men want his brain. The X-Men discover this, defeat Sublime who is killed in the struggle, and free Xorn. Xorn then joins the X-Men, as a healer.
With that story over, the next plot moves on to involve Cassandra Nova once more, and I won't go through all the details here, sufficed to say that part of her plan is to weaken the X-Men with nano-sentinels that are so small they are inside the X-Men, hacking away at their cells making it seem like they just have a cold, when in fact, they are being killed from the inside. Xorn, who has the power to heal people, heals all the X-Men by placing his hands on their head and through his power, killing all the nano-sentinels in their body. Cassandra Nova, who has possessed Charles Xavier, makes her final attack, and Xorn jumps on her, "healing" her, which somehow weakens her momentarily. The rest of the story unfolds and due to Jean's clever planning, the day is saved. But it turns out that Charles can now walk.
A while later, the X-Men return to Genosha because of weird occurrences there. Someone, amongst the radiation-heavy debris, is constructing a Magneto statue. It turns out to be Toad and some other mutants, and then there are these ambient magnetic fields, which turn out to be a farewell message from Magneto. He talks about his life, his dreams, his goal, and his untimely death, and gives a beautiful send off to the world.
Morrison has also, a series of unconnected events occur, for example, one student called Quentin Beck decides to orchestrate a riot in the school, during which another student is killed and it causes horrific public relations problems for the X-Men. As Quentin Beck is dying, Xavier calls Xorn in to heal Beck, but claims he is unable to do so. Other events such as a drug called "kick" which enhances a mutants power but is extremely detrimental to their health is being used (indeed, Beck is thought to have had an overdose of it), as well as more U-Men, and the discovery of the Weapon Plus programme, where it discovers that Weapon X is not Weapon "X" but rather Weapon Ten (X being the Roman numeral for 10) and Wolverine learns that there is a Weapon XIII, Weapon XIV, Weapon XV and so forth, and that they are all bred in a self-contained biosphere called "The World" and they're supposed to be next-generation Sentinels. Emma Frost is shot and killed by an unknown assailant due to having an affair with Cyclops (she gets resurrected though by Jean Grey), and more and more stories are happening.
Then, as Wolverine and Cylcops are in the Weapon Plus programme's HQ (which is a satellite in Earth's orbit), Jean goes to help them out, while Beast and Emma fly half way across the world to follow up a lead. In Xorn's special class, a girl called Sooraya (which is also my sister's name, how odd is that?), becomes frightened and her powers runamuck, destroying Cerebro. Xavier tries to help, and Xorn starts talking to Xavier very differently. Xavier notices that there are posters in Xorn's classroom that say, "Magneto Was Right", and then Xorn explains that the reason Xavier can walk is because the nano-sentinels Xorn put in his body are allowing him too, at which point Xorn gestures, and Xavier becomes crippled once more. At the same time, Emma and Beast are in the Blackbird, which explodes due to sabotage, and Wolverine deduces that the Weapon Plus HQ is Asteroid M. Xorn, then takes off his helmet and shows Xavier that he's Magneto, and that he's been planning this for a long time.
Magneto then destroys Manhattan, and turns it into New Genosha, and tries to usher in a new world. He's crippled electromagnetism the world over, because his message was actually a virus. The problem is... the mutant populace don't believe that it's really him, since he's died so many times. Magneto intends to turn the world on its axis, and needs to use the kick drug to do so. The X-Men regroup and confront him. In the ensuing conflict, Magneto is defeated and told to give himself up. Instead, he discharges all the power he's been storing into Jean, killing her. He then tells the X-Men to make him immortal, and allows Wolverine, who is in a frenzy, to kill him.
That's not the end of the story, but it is the end of Xorn and Magneto.
Xorn was just a guise Magneto used to destroy the X-Men from the inside. It was masterfully done and you should check it out.
But anything done with Xorn after that is a big waste of time.