I'm also in the camp that Nathan is not dead. If they don't show a body, he/she ain't dead. And even then.

Obviously Grandman was involved in some kind of Spectre thing, so there are probably other Illuminati wandering around, most likely with sinister powers.

And that Noah line was hilarious. The whole thing was a tad cheesy. "You saved the cheerleader so we could save the world." Who says that?