Fourchenault --
after Zenos, Fandaniel and the ancient primals -- will be the character of the final boss that has to be addressed before whatever series mascot (ahem, Zeromus) that is the final trial.
A sane person would observe that very little from the trailers ever happens in quite the manner shown, but I'm taking Fourchenault's lines in the trailer as seriously as a crackpot.
Y'Shtola:"So, Sharlayan would keep its council while the world is lost to ruin."
Fourchenault: "It would. Come what may, we shall live on. We must."
- What incentive do they have to abandon the world? Speculation: Sharlayan has something to gain.
- Fourchenault seems pretty sure they're going to 'live on.' I think this is because he actually knows that they will.
So, I wonder whether Sharlayan has a place they know they can go to survive. Like the past. Where they directly, knowingly causes the Sound. And as they watch history repeat, they harvest the fractured worlds and then rinse and repeat.