Farronite Republic and Terran already out-gun Asylon, so, as far as I'm concerned the war is a foregone conclusion. A crusade won't matter one bit. Even if the outcome of the war was unsure, half of the crusaders are too far away to do anything. The other half have, or have probably, already made up their minds to join on their own volition. In any case, a crusade would merely be for show.
One thing that will be interesting to see is how the victors manage to overcome their lack of spare nobility. Ideally, the SA realms would want to destroy Asylon utterly and set up a new realm, drawing it's ranks from their own nobility. But they cannot do that, as, between all of them they have only an excess of roughly a dozen nobles. Even if all twelve of them wanted to migrate to the new realm they would be short by three, as Asylon has fifteen regions that would need to be governed. So, this conventional strategy of realm-founding wouldn't be particularly viable. Other strategies, such as looting Asylon's regions to revolt, in order to destroy it and leave the lands as empty husks, would probably be too much effort on the players' parts. Who would want to continually journey back and forth looting and refitting over and over again to the extent necessary for cleansing such a large area? Probably not many people. Asides from those two strategies, I cannot think of a way to resolve this war in a consequential manner. Any resolution which leads Asylon alive isn't much of a resolution at all, as Asylon could merely start the whole thing anew without suffering any consequences which it would have not already suffered. Basically, thanks to the lack of will-to-power on the part of it's enemies, Asylon is eternal.
No need to cleanse a whole area. Just TO a few cities, loot the other cities rogue, and the realm will collapse. No need to focus on their bunch of rurals.
