Great looking mod, my two bits. Crusades are a part of Warhammer, period. Crusades were launched by the Empire, Brettonia, Tilea (and the surrounding regions) against the Skaven, Araby, and to a certain extent the undead. I will dig up some fluff sources when I get off work .

Warhammer really does boil down to a fight between good and evil, bearing in mind that both sides don't mind fighting one another along the way. It is important to point out that there are at least two distinct camps. High Elves, Wood Elves, Dwarves, Brittonia, The Empire, Kislev, the Border Princes, the Tilean City States, all of them can and do make alliances, and support one another. But you would never see them making an alliance with Choas, Beastmen, Skaven, Undead, Dark Elves, Choas Dwarves, or Fimir. Orcs and Goblins fit in there for the most part as well. There are a couple of groups that seem to swing both ways, as in are more neutral parties, such as the Slaan/lizardmen, Hobgoblin Hegomy, Araby, and some of the tribes between Kislev and Choas Wastes. You could also throw Cathay into that mix for good measure. The point is, there are two main groups who DO NOT tend to mix well, and modifying the existing religious structure could be a way to do that. How would I do it, if I could? By alignment/motivations.

Lawful/Good

Neutral/Some Evil

Choatic/Rest of the Evil

I have heard different numbers for a religious cap in MTW II, Some say six, others 7, I will shoot on the low end, at six.

Religion 1 “Catholic” (Neutral, crusading kingdoms)

Empire
Brettonia
Kislev
Tilean States
Border Princes
Estalian Kingdoms
Dwarves (reclaiming lost dwarf holds, grudges, etc) (could be orthodox instead)

Religion 2 “Orthodox” Good, Lawful, Tend to be Isolationist, no crusades /jihads
Wood Elves
High Elves

Religion 3 Chaos Worshippers “Muslim” Jihad, Evil, Chaotic Evil Races (have history of mass invasions)

Khorne
Nurgle
Tzeentch
Slaaneesh
Beastmen
Orc and Goblin
Skaven

Religion 4 “Heretic 1” Non Crusading/Jihad Neutral (even a little evil)

Old Slaan/Lizardmen
Hobgoblin Hegomy
Northern Steppe Tribes
Araby
Cathay/Dragon Isles


Religion 5 heretic 2 non jihad evil races

Vampire Counts
Tomb Kings
Dark Elves
Chaos Dwarves

That gives me

7 “catholic faction”
7 “muslim factions”
2 “Orthodox”
4-5 “heretic 1” factions
5 “heretic 2” factions


The key here is you have you two main divisions, the catholics and muslims. Those in one camp despise those in the other, meaning that although they could be allied for a short period of time it is unlikely to endure. The orthodox factions should also have enmity towards the muslim ones. Heritic 1 factions are could go either way, while heretic 2 factions are the opposite of the orthodox and would tend to lean towards aligning them selves with the “muslim” factions.

The different “religions” are more like levels of tolerance. You can stratify the groups with different cultures, just like you have northern and southern European cultures, we could stratify the catholic factions into:

Northern European
Empire
Brettonia
Border Princes

Southern European
Estalia
Tilean States

Eastern Culture
Kislev

Dwarves, who knows. If I understand the game mechanics correctly though this stratification also causes unrest, IE having a SE Church when you are a NE factions causes some unrest until you upgrade it or destroy and replace it. I assume the same thing could be done to separate the Muslim factions into a chaos culture, ork and goblin culture, and skaven culture.

Just my two bits LOL. I am willing to help as needed, but I do not have extensive modding experience in MTW II, though some in other games like Morrowind. I do a bit of petty messing around with basic game files, nothing fancy.