Caligus will come, or they won't. Xavax doesn't particularly care anymore. There's a certain glory to fighting all the major powers of the island and then some.
The thing about Xavax, however, is its location. It's so far from the capitals of other realms, and its own regions are so close to ITS capital, that we can make this a long and bloody war. I already gave a variation of Bill Pullman's Independence Day speech to the Xavax nobles.
That said, how long before the whole island falls back into war I wonder?