that whole vampire talk somehow makes me want to have a "vampire masquerade ck2" now... with maybe a map of the US or a few (6?) nearby big towns split up in districts.
a "kingdom" would be that you are the "ruler" of a city then... and several vampire clans and humans all trying to control districts in cities.
stuff like castles, towns, church could be different shops then in the districts with different boni. a weapons shop could give you access to gun troops... or a +10% to attack... or a pawn shop more income... or a homeless shelter or a newspaper or something could give you +10 opinion with humans.
troops could be different gangs, police, army, hunters, ghouls, vampires, other monsters that maybe live in the nearby mountains and woods around the towns attacking every now and then the humans try to defend against with police and walls etc or even if you play as vampire you might want to fight them so your districts are in good shape and not every human murdered (viking raids?).
maybe different vampire clans (cultures?) can use different troops... mages use golems gargoyles? ... forgot the names of the clans in vampire masquerade... tremere? there was one "pretty" ones maybe they can use influenced human gangs... the "ugly sewer" vampires maybe could use some sewer travel system to get around? (boats= sewer? or water on the map = sewers? or boats = taxis/busses/cars?)
maybe you could even simulate a "city life"... you spawn humans (troops) from residential buildings... and they try to walk to parks/entertainment/work industrial/parks etc places/districts and maybe they "relax at the park" or "work" or "go shopping" as a "siege" event mechanic that keeps them there for a bit...
probably wouldnt work... like making "residential faction" hostile to "shops and work" so they walk around or so... haha
but i feel the whole ck2 people mechanics and controlling areas might work pretty good in a more "modern vampire city map" or so hmmm
and traits etc could be stuff like: "police" -10 opinion to mafia/gangs/criminals and +10 supressing rebels... "vampire" and "vampire hunters" have - opinions with each other... cultures could be based on the towns too so that town X people might not like town Y people"... who knows...
maybe some sort of "city generator" (
https://watabou.itch.io/medieval-fantasy-city-generator) could be used to make 5-6 cities.. link them all together... add rivers and woods hills stuff around and in between. turn it all into a ton of districts to control and have people in for ck2... but then again i have no clue about ck2 modding and map modding and all haha.