Hi, everyone. Long time reader, first time poster. I looked around the forum to see if this particular topic had been posted. I didn't see anything, but if I'm late, I apologize.
For those that read New Avengers and Avengers, we know that the Multiverse is dying. As the Black Swan said, "At the birth of Rabum Alal, the early death of everything began". But who is Rabum Alal, and where did he come from?
On my lunch break at work I was rereading Fantastic Four #600. In that story, Reed and Sue Richards have a conversation with Galactus. He tells them he is staying close to Earth, because the Asgardians have the Galactus Seed hidden in the World Tree. If Earth is destroyed the Seed will be lost to places less accessible to him. The being inside the Seed is an aberration. Something to correct a thing that isn't broken.
Sue then asked Galactus if the being inside the Seed would be better than him. Galactus said it would not. It would be immature and that "everything would end much sooner". Then it clicked: Rabum Alal is the being inside the Galactus Seed. On an alternate universe, the Seed hatched, and it led to the destruction of that Universe, the cascading effect is causing the Incursions.
Im at work so I can't post screenshots, but I think its a solid theory.