Is the Crimson Throne from an established cannon somewhere, Doc? I read through your sheet and didn't notice anything that confirmed that he couldn't exist in a generic post-apocalyptic setting. How about confirming a few of the basic tags/requests/interests? Even if the Crimson Throne exists in a different multiverse and some of the details have to be fudged the Crimson Throne in and of itself is a useful actor for this purpose. Kull himself may be a, "nice guy," but empires don't arise from the actions of good people, at some point the Empress/Emperor actually conquered at least one other society to gain the title, or so I assume. This creates the plot need for those who are actively opposed to the Crimson Throne's rule, if only because they want a bigger slice of the pie over their own territories for themselves. There's always the angle of the popular revolution, though given the request of, "apocalyptic underground society controlled by rival gangs struggling for control over a specific sector," I would propose instead that what is going on is that a singular primary opponent, either a populist movement headed by a charismatic leader or a single faction larger than the individual gangs one on one but significantly weaker than the gangs as a whole (some 60/40 or even 70/30 split would be fairly realistic) who are dependent on the separate gangs to not turn on them en masse but to whom these individuals aren't exactly, "friends," nor desired in the long term. This would allow for these individual gangs to both be able to fight with one another over territory, and to have two separate, "superpowers," fighting over general control of the city/territory to occasionally cut deals with in return for resources. 

I would propose that the surface world is covered in a permanent ash that has essentially obviated farming as a practical food generator, and what has taken over in its stead is a heavy dependence on less light intensive plants, fungi and night blooming plants, and the shepherding of animals who can subsist off of these plants, with water being the most singularly important resource any town can possess followed by access to a workable metal for tools/weapons and the tech needed to accomplish this. Most people live as slaves scattered in small groups across the wastelands and ruled/owned by various competing warlords who are locked in a constant struggle between the established superpowers in the region, most notably the Empire of the Crimson Throne whose high towers and walls of stone have been built up and around the remains of an ancient city of glass and steel (Doc’s choice as to the real world location), and the Children of Aberforth, Archibald (or Archimenon, whatever) the former Court Wizard of the Crimson Throne. That isn’t to say that magic is real in this setting, the wizard may well be a delver of the old places who gained knowledge that permitted him to teach the Crimson Throne building techniques, weapons manufacturing, etc., that permitted their empire to rise above the slaver collectives and attain their lofty heights until he decided that they hadn’t done enough to stem the injustices in the world that led him to teach them these old world secrets in the first place and left to form his own faction opposed both to the slavers and the Throne. 

From this point we enter the city of Karitos, nestled in a patch of mountains pocked and cratered in the aftereffects of whatever tragedy befell the old world and borne the new, consisting of old sewer tunnels, a complex series of half-collapsed basements and natural mountain caves more labyrinth than traditional city. There is no such thing as a grid layout here, and it could take you so long to get to the physically closest living space from where you are as it would to cross the underground city depending on the environmental factors and local degree of collapse. Natural water is easily accessible from all of the districts in the city, and the heart of the town for which the city is named is a natural cave with free flowing ground water by the name of Karitos (or Heart) of the Mountain. To control this point would automatically make you the ruler of the entire town, for though other districts have some amount of water themselves there is no other point from which the entirety of the population of Karitos could possibly sustain themselves. No wonder it’s also the most heavily contested and watched over point by the various gangs and factions operating in the area. The common convention accepted by the people of Karitos is that the districts, each ruled over by one or more gangs local to them, have equal access to Karitos and that no weapons are permitted inside, with all factions keeping a permanent guard and defensible position from their individual entrances pointed towards the heart as both a forward strike base and in case of any funny business on the part of the other gangs into Karitos. 

What makes the city itself distinct from both the slaver gangs and the freeholds of the wastes and makes its people of specific interest to the Crimson Throne and the Children of Aberforth is that they rest atop a bastion of ancient writings and knowledge that is kept bared from the population by only a few meters of debris. The problem for all sides is that this bastion is located in the remains of the super structure constructed directly above Karitos in the old world. A museum in relatively good condition owing to its collapse into the earth before the worst of the damage to the surface world came to pass, whose knowledge of the old world and its technologies could shape the next century of human development, and hand the keys to control over the wastes to a single faction or individual, and though it would be beyond any side’s abilities to dig down hundreds of meters to get into it from above any side with a solid dominion over the city of Karitos could tunnel up into it in a matter of days. 

This city-wide dominance is something that no side has been able to accomplish as of yet. The Superpowers have refrained from storming Karitos directly in an attempt to keep from unifying the population into a single fighting force, and one that would potentially ally with the other side indefinitely should they be faced with an outright invasion by one or the other, and neither side have so much as a definitive foothold in Karitos proper. The local gangs are consistently untrustworthy over long stretches of time, and are more likely to cut temporary deals with one side or the other for their resources before shirking back to neutrality, as likely to cut the next deal with the other side as the former. There are a handful of gangs who have only ever been neutral or temporarily aligned with one side, but these represent about thirty percent of the population split roughly even between the Crimson Throne and the Children of Aberforth, and are by no means to be considered legitimate loyal soldiers. That isn’t to say violence isn’t an everyday, commonplace event in Karitos. They’ve even managed to make a spectacle out of the event. The one and only situation where weapons are permitted in the Heart of the Mountain is when two factions have a disagreement and challenge the other to a duel before the eyes of the townspeople. The only place that can be witnessed by the entirety of the town is, of course, the center of the tunnels and sewer networks. Roughly circular and approximately thirty three yards in diameter, the factions gather to witness the spilling of blood in the Heart, and once a duel has been issued and accepted there is no end but on that hallowed ground. 

Beyond the duels in the Heart the factions, though they all meet in the Heart, are still interconnected in other locations along the complex underground systems. None of the factions hold territory that is completely inaccessible from a location held by another gang, and in these contested hallways and open caverns and basements battle rages near constantly in an effort to gain more influence, more territory, and more control over the next group. The fighting is fierce, and often moves inch by inch with projectiles lobbed at the opposing side’s palisades or shield walls until both sides reach a breaking point and charge one another with bronze dirk and iron battleaxe at distances of a mere handful of yards. Each gang controls several important locations noted for their production capabilities, food or water harvesting, or natural resource reserves, and the blood spilled by their soldiers is always considered to be worth the price when taking or defending these priceless resource generators. 

I think this would be a useful starting point for further discussion, but of course take or leave as much of it as you both want. It simply accomplishes the goals of having the potential for two superpowers warring over a conflict zone, underground gangs fighting over smaller points of interest, an arena that has plot background for being used to generically spill blood, plus it could easily transition into a Nation Roleplay. That would either be accomplished by players reprising the as of now faceless, “gangs,” of Karitos or even as totally independent freeholds or slaver gangs in the Wastes who are trying to compete with the superpowers and each other for dominance over the wastes. It can also be filled in with setting details that would allow it to fit the category of Post-Apocalyptic, Future, Medieval, Sci-Fi, Fantasy, Military, or whatever really, and so few as two or as many as might join could realistically take part in the setting in one form or another. If you do want to try it out as a 2v2 or something in this setting (modified, not modified, or even scrapped entirely) I would be happy to write up a character for the fight, either with you versus Doc and his second, or with Doc versus you and your's. 

[hider=Important Information ~ WIP] 

[hider=Setting Specifics] 

[b]Technology[/b] 

[b]The State of the World[/b] 

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[hider=Factions] 

[b]Super Powers of the Wastes[/b] 

The Empire of the Crimson Throne: 

The Children of Aberforth: 

[b]Gangs of Karitos[/b]

[b]Slaver Gangs[/b] 

[b]Freeholds[/b]

[/hider] 

[hider=Persons of Note] 

[b]PCs[/b]

[b]NPCs[/b] 

[/hider] 

[/hider]