You win the game by keeping Athjeari alive through to the end.
Ah look, another of the Athjeariati. Athjeari's Wind Mills? (do you call the non-believers Athjeariatrics
lol)
Anyway, your game would be way better than a straight Total War conversion. Again, I'd buy lol.
As you described it, it kind of plays out as various versions of Kellhus' probability trances, cycling through "What If's" except you have to play through a whole campaign.
Could do something even more meta and make Kellhus the 'main character'. If you split it into campaign levels, each one you'd set out to collapse the probability curves, lending to 2-3 different endings for each level, further affecting each next campaign level. Necessarily, at some point if you took the wrong paths you get stuck at a dead end and end up an unavoidable casualty forcing you to restart or find an old save that's before your point of no return.
Start of each level you advance real Kellhus to the end of the story, do some 'real interactions', then probability trance again, play out the scenario, advance real Kellhus, etc.
Hmm, or maybe play it out in 'real space', but each time you die you respawn at save points which are ostensibly the same thing as described above - like 'oh, you're in his head and that line of actions lead to your death, try again'. Essentially Dark Souls (and/or Assassin's Creed), but you're Kellhus, at bonfires you sit down and meditate/probability trance. Beat the game, unlock "White-Luck" difficulty (or Survivor Difficulty) - no saves, death brings you all the way back to Ishual. "Any wound save that which is fatal". (Narindar Achievement - an entire play-through without a single hit taken on White-Luck difficulty).
DLC could include Cnaiur in his early campaigns against the Empire, Cishaurim infiltration of the SS, scholastic wars, or go more into Horror and do Survivor in Ishual, raiding the Ark, etc. An infinite number of possibilities
Full expansions or alternate campaigns, you pick Achamian, Cnaiur, Conphas, etc. to play through. Same war, different set of influences. And who doesn't want to burn down the Sareotic Library, the SS Compound, murder a few Ciphrang. (Achivement: Why do I always get the Stone? - lose to Xin while playing Benjuka as Achamian).
