"Magneto: Not a Hero" #1 isn't a bad comic. It is a mediocre, somewhat obvious comic. In telling a Magneto solo story highlighting his role as a member of the X-Men while reinforcing his not-so-heroic (hence the title) nature, Skottie Young delivers a story that's fairly simple and not surprising in the least. Magneto has apparently slaughtered the attendees of an anti-mutant gathering, except he was somewhere else at the time. It plays upon his villainous past, while allowing the character to push forward and show that he's changed. There's nothing wrong with that approach; it's merely the most obvious one.
When Cyclops and Magneto meet with Captain America and Iron Man about the video footage of Magneto killing the people, you almost want to say "Of course he was with Cyclops at the time!" when that fact is revealed. The mistaken identity/frame-up plot is so overused that it's hard to guess why it's being used again here. Will the second story arc have an old mutant follower of Magneto get killed by humans and a conflict brew over his desire for revenge and his loyalty to the X-Men? Like I said, there's nothing inherently wrong with this sort of plot since it brings to the forefront the necessary conflict, it's just disappointing that Young and Marvel couldn't come up with a more original way to do that.
Within this framework, Young writes a solid comic. The meeting between Magneto, Cyclops, Captain America, and Iron Man features some good dialogue. Young manages to write the two X-Men as firm and independent without having them look 'evil,' while the two Avengers come off only a little patronizing. The only misstep is Magneto going a little too far with a demonstration of his powers in an effort to show that he's still got his edge. His 'acting out' to a large enough degree that it should have destroyed what progress was already made.
The demonstration of Magneto's powers to Iron Man seems forced into the comic to bolster the visual excitement and stands out for that reason. It's a surprise that an artist wrote this issue for that reason. Aside from the opening shot of 'Magneto' and the final pages that take place on the mental plane, this is a comic with little visual flare. Clay Mann adds some excitement to the talking heads scenes with unconventional angles, but, like the addition of Magneto going overboard, pushes things too far at times. This is a world of stiff poses and constant demonstrations of energy-based powers. He's much better as an artist when he pulls back a little, like in the way he shows Magneto's indifference to what Captain America and Iron Man say.
"Magneto: Not a Hero" #1 is an okay first issue. The plot is obvious and facilitates the necessary conflict to showcase Magneto as both an X-Man and as someone with his own agenda. Scottie Young has Magneto's voice down and Clay Mann draws him well. The reveal at the end of the issue is a logical one and provides for an interesting antagonist going forward.