Much like Demon Prince, Last Stand would have one very powerful enemy and a bunch of nobodies trying to defeat it. Lithyl would be a great villain for this.
-Lithyl Nightweaver starts with 3 cities, a maxed metropolis, 5 more levels and enough resources to start invading players and free cities.
-She cannot ally anyone and her goal is to conquer everything.
-Whatever she conquers will be reduced to ruins.
-If you take too long to defeat her, she will auto-befriend the cities of the umbral abyss, making it a lot harder for the players.
-Also, gloom is marching towards your lands.
-She can and will attempt magic victory eventually.
With this scenario you can pretty much play Alfred Elderstone's origin story. And it looks like it would be a lot of fun.