Yet Another Few Siege Teasers: Norman's Secret Weapon and Look, up in the Sky!
The most likely one's (assuming this is supposed to be the shadowy guy from some time ago) are Mephisto and Beyonder.
Beyonder since he's the one whose part of Secret anything after all and he's been MIA since The Illuminatti mini, and I doubt that's him in the last Dark Avengers issue.
Mephisto: Wouldn't it be a hell of an ironic thing to find out that OMD was purposelly orchestrated by Mephisto so as to reshape reality and make it easier for the villains to win?
X-Man is a huge unlikely choice since Norman's X-Men are supposed to be getting into fights with him soon and power or not i doubt he'd make Doom and the others scared enough to work with him (even if Doom is never scared)
No way it can even be Odin whose stuck in another dimension fighting off an invasion to protect Midgard or somesuch and he wouldn't sully himself by working with Norman.
Scarlet Witch? Shadowy guy looked male. And Wanda is apparently leading a quiet secluded life recovering from HoM.
Dunno who the fellow on the middle left is. An Eternal?
Thanos is dead, though a copy of his showed up in Pet Avengers...Not to mention the shadowy guy looked human.
Next... a unknown figure flying over NY.
Bad guy good guy? No way of knowing. I'd like to assume the people are panicking and that's Void in Sentry esque form.