You could start a pure Priest character, I have tried a few times but just can't get the enthusiasm (or skill) to carry on for long with them.
Restrictions you can try;
Male (for the tonsure hairstyle
), choose the Priest or civilian options where available, for characters start & father died option.
Only hire the nicest,most pious companions, if you want any that is.
You and the companions will only use Robes,hoods, clubs, Quarter staffs & stones. All starting gear & loot is sold, but may keep a herd of horses in the inventory, Unarmoured horses can be ridden.
Hire peasants from what ever faction you want but
never upgrade them, ideally you want your army to compose of only troops from the Pilgrim troop tree... eventually.
From level 2+ never learn any military skills, but weapon skills can be upgraded.
In a battle command your troops as you wish, but you can never engage an opponent except in self defense. Only evil men/women/Lords can be taken prisoner & sold, all peasants, farmers, faction troops will be set free to return to their families and give up this life of warfare.
You will help every village you pass, but only help guild masters once in order to set up an enterprise. The only enterprises you can set up are the bread & Winemakers.
Now I am not sure how you would handle becoming a vassal & uniting Pendor as I have never got that far