I am not the best guide as I think myself the layman in 40k but basically it was a pen'n'paper RPG setting (originally just warhammer without 40k) of futuristic, very grandiose sci-fi that over time turned into entire franchise with video games, books, animation movies etc.
Basically in this setting there is God Emperor sort of that rules everything and has lots of orders. Basically the social structure, to put in in coder's language boils down to:
if problem - apply terror
if solved - good
if not - apply more terror
rinse and repeat
Inquisition is the top branch of the tree. When they find signs of heresy they don't throw the baby out with the bathwater, they throw the entire kindergarten out with the bathwater.
I believe it translated well into Obia'Syela, since early Inquisition in OS was the one time I had the inexplicably awesome opportunity to enjoyably balance on the edge between being rewarded and being executed.
