Age Of Ultron's surprising ending is meant to be top secret, only eight people are meant to know about it and Joe Quesada is drawing the last few pages to preserve the mystery. Nice bit of PR, certainly but it's not true.
Guarding the secret has been Marvel's number one job, but it seems there more than one aspect to Age Of Ultron's ending that they are trying to keep confidential. Everyone seems to think I love to spoil stories but it's just not true, when I discovered one aspect to the ending of Age Of Ultron after the Marvel Summit, they asked me not to run it, so I didn't (even though it screams at me from this month's solicitations- could only eight people really know this one?)
Later, however, I was told a different aspect to the ending, which caused Marvel to properly panic when I shared with Marvel that I knew it – or at least a part of it – and I was told there were all sorts of legal implications if this story got spoiled by me. And so, again, I'm not running it, but I will give you a hint because you deserve at least that, "an unexpected guest star joining the Marvel Universe…"