Last week was tumultuous in terms of the comic book industry it seems. 'Twixt Wondercon and Megacon (and MoCCA), with the Marvel writers retreat and DC Comics execs flying in for the final week of the publisher in DC Comics, Mike Marts quit Marvel.
Marts is a relatively recent hire, headhunted last year by Marvel from DC where he was the Batman books editor. As Executive Editor, he has been editing the X-Men books at Marvel ever since.
Until last week, when he quit Marvel Comics for an unnamed publisher. However, I understand he is still on good terms with the publisher and remains "part of the family".
As to where he is going… that could be an even bigger surprise.