I had something in mind, and then Jorick convinced me, and then with Brovo's post I re-convinced myself. I'm personally partial to saving Liveria, Rheinfeld, the Free Holds, the Imperium, and the Underdark. However, I'm reconsidering
again because of Brovo, so yeah.
The Free Holds I would choose to abandon because, as Brovo said, they are basically unbeatable. Of all the nations, they can probably take the most damage. If we're lucky, the Holds will go into war with each other over this new Warband leader's demons. It'll take a long time for them to go down, and they are likely the nation with the easiest return to status quo. However, it is entirely possible that due to the influence of this succubus, that the Holds might actually unite, and hell-on-earth would that suck. The demons are already an almost unstoppable horde, and with the Holds on their side, we're basically doomed. So of the ones I'm considering ditching, the Holds I'm most considering switching in, potentially by ditching the Amazons, as much as I hate it.
I would abandon Liveria because firstly, they aren't a large nation, and they are isolationist. They are stubborn, and they can probably hold off enough not to be completely wiped from the board if we ditch them. However, now that the Angels are over there, I'm starting to think I'd rather go for them. As was said, the Angels are an ideal and logical choice for fighting demons, and I wouldn't want to lose them.
Unless there's some new super-important reason in the next OOC post, I'm now thinking we should abandon Renalta. What does it have? Well, a perfect society that we all love and adore, sure. Lots of great people, some significant NPCs, highly defensible with Liveria and... Well, the issue is, Renalta and Liveria are separated by a full-scale mountain range from just about everywhere else. This either makes it a great last stand, or very annoying for mobilization. I want to save Renalta, but they aren't very useful until late in the war, where they can either become a refuge with great defense, or a useful pincer-point with the Goblin Holds. That, to me, is the extent of their utility, and I say we can bear to lose a little ground back home because we can always retake it later, especially with Liveria's help.
The Underdark I would save because boy is that a lot of ground. Those caves can be very useful for getting around in the future, and I don't think we stand much chance of navigating them unless we ally ourselves with someone down there. I also imagine demons will be working their way from down there in part anyways, so while it may not be the easiest place to defend, it will give us an early warning on when to protect ourselves.
Rheinfeld just always seems like a no-brainer. Big country, lots of useful anti-demon stuff, also some nice variety between the Templars and the Republic, if we can get both on our side. If we lose the two Southern states, this would be the place best suited to resisting them. If we don't, this would be the easiest army to retreat back into Renalta. In almost all situations, Rheinfeld should be saved, the exception being total devotion to the pincer tactic, but then we would at least need Tuleria's navy to cross the Blood Sea. Rheinfeld is just overall a good base of operations.
The Goblin Holds? Meh. Small nation, little geographical use. I'd see the Free Holds as a more useful ally, even though the Goblin Holds play more to our Renaltan sensibilities. If their ingenuity is really that good, they can sort themselves out, and see that helping us out will be good for them in the long run. And if they get eaten by the Free Holds? Well, no land lost, anyways. We can easily access the Blood Sea elsewhere.
Tuleria is a very tough choice. Their main advantage to me is their navy. Not because, as Temptress so passionately cries, it's our access to the outside world—the outside world is of little use to us right now. Limitless ocean isn't going to come save us, and the nations out there are probably handling their own affairs. What I see as useful is if they can get their navy over to the Blood Sea. That can be a big help, because while the Goblins may be able to hold their own, we're gonna need some help down South too. If we can get the invasion confined mostly to somewhere in Rheinfeld or the mountains, those boats open up a whole new front that could really squeeze the enemies between our forces. Divided we fall, and all that. So if we want help from the Free Holds, we'll be needing Tuleria too, even if they are across the world.
The Amazons are great and all, but sacrifices have to be made. I get the impression their assailant, while extremely powerful, is not going to do well in a desert, so the only other place it threatens would be the Imperium. (We'll get to that in a second.) Their powerful fighters would be very useful, yes, but from a geographical standpoint, they don't have much to offer. Getting them across the Blood Sea will be a hassle, with Tuleria being on the other side of the Sea, a big delay for our naval back-up.
The Imperium are another tough choice, one that I very much would like to save. Like the Amazons, they are of little use geographicallys, which is my focus here. However, they may be able to help the Amazons rebuild later down the line, which would be nice. They also feature a pretty epic army. I would love to ship those soldiers to that bottle-neck mountain valley between Renalta and Rheinfeld. As a last stand, that would be near unbreachable, if we could convince them to come over, which I hope to think wouldn't be too hard, considering their adaptability.
So who should we save? Geographically, the best bets would be Renalta, Liveria, Free Holds, Tuleria, and the Underdark. That would allow us to surround enemy forces while maintaining some mobility—being Tuleria across the Blood Sea, ships between Liveria and Tuleria, and the underground tunnels for pretty much any surprise attack ever. However, the Underdark would be hard to defend, and so it is the one I'm most willing to drop, despite our Drow brethren.
In terms of military advantages, I feel like Rheinfeld is the top choice, followed by Liveria's angels, then the Free Holds, and finally the Imperium. However, Tuleria's ships are important for mobility, so throw that onto the list with the Free Holds, even though I consider them more of a utility. The other armies I feel we can afford to lose.
Unfortunately, that gives us some tough choices. After even more deliberation, I'm now vouching for Free Holds, Tuleria, the Imperium, Rheinfeld, and either Renalta or Liveria, hopefully whichever we choose can back up the other.
What about the missions you say? I'm not really considering those yet, waiting for Brovo's post. This is a preliminary study based primarily on the tangible geographical and military assets of each nation, which are far more set in stone than "ooh princess".