I am the Black Wizards said
Other than hating the old kingdom, what is the Order of Idris all about? Like what's their doctrine and why do they hate the old kingdom?
I recommend the lore section on The Dominion of Idris. There I have explained why they hate the old Kingdom. Their primary focus is destroying all relics and their users, since they belief that will recreate the equality amongst humans and prevent an enormous amount of suffering. As Ellri said, they have a slightly odd sense of "equality", since women are barely worth a thing to them, though they do try to ban the slavery that's abundant on the western side of Azukhar (mainly in Oragos, Harra and Da-Hyun).
We haven't really decided how exactly their power hierarchy will function, but I want it to be different from Roman Catolicism no matter what (seeing how their inquisitors already resemble that faith slightly). So if you have any suggestions, feel free to pm me, another GM or just throw it up here ^_^