I’ve seen this in a couple places, so I activated my giant brain and put some thought to it. 72 hours later, I have a solution.
Short answer: they don’t.
Long answer:
In World War Hulk, Sentry is shown as unresponsive and noncommittal. He has yet to lift a finger to help the anti-Hulk side.
In a recent issue of Mighty Avengers, so recent it just came out yesterday, something happens. Lindy Reynolds, wife of the Sentry, is apparently killed by Ultron. I say apparently because there is at least one 100% fake death in the series already, not to mention the fact that Ultron can create appendages and probably change shape.
People are linking this and WWH to explain why Sentry is so out of it. Here’s a simpler idea–
The Hulk is a good friend of Sentry’s. He’s only calm around the Sentry, so the Sentry has kind of a paternal love for him. He wants to be able to help him as best he can. And then, one day, Hulk comes back and blames Reed Richards and Tony Stark for firing him into space. The Sentry’s own friends betrayed Hulk.
And then they come to him and ask him to help the Hulk… by taking him down.
When they ask him to help, Sentry asks Tony for a moment. He wants a word with him. My bet is that Sentry asked Tony, “Is it true? Did you send him into space?” and Tony said, “Yes.”
That’s why he’s sitting on the sidelines. His own friends are using him.
WWH is a good story and it stands on its own. It doesn’t need Mighty Avengers and it’d be foolish to tie that in.
WWH is about old Hulk vs new Hulk. His new friends vs his old friends. General Ross shows up in the last issue. He’s an old enemy, but his daughter was married to the Hulk. She’s dead now, I think. Hulk’s invading Earth because his wife died. There’s your drama right there.
The Rick Jones = Miek thing is pretty dumb, though.
WWH, when you boil it down, is about relationships. World War Hulk: X-Men is proof positive. (It’s also the only tie-in I’m enjoying.) The X-Men, even after all the crap Xavier has put them through, stand by their former headmaster. Xavier is willing to give in, but the X-Men are a family. All for one and one for all. It’s pretty good stuff.
I’m betting that the big fight in WWH isn’t Hulk vs Sentry. Not at all. I feel kind of like it’d be an depowered Hulk (read: Banner) versus Bob Reynolds. It’s just a hunch.
Oh, and Spider-Man: One More Day isn’t about Mary Jane dying at all. That’s a smokescreen. Joe Q is pulling the wool over your eyes again.
It’s about Aunt May getting one more day with Uncle Ben, or maybe her family, before she dies.