I really like the idea of running a game where the warband basically gets to officially troll/BLAM! the Ecclesiarchy. Unfortunately not much info exists on the Ordo Sanctorum so I figured a community thread for ideas about them was in order.
My Ideas so far:
What happened to your planet's Ratling population? Abhuman citizens of the Imperium tend to get ethnically cleansed when Fanatic priests roll into town. Though second class citizens their lives belong to the Emperor and wasting those lives due to blind bigotry is heresy.
You aren't the Emperor's special chosen prophet sent to guide Humanity to a knew golden age! BLAM!
You declared a War of Faith, that's a BLAMMIN! So I read 90% of people who call in an Exterminatus are declared Heretics and executed. I like the idea of that applying to Wars of Faith as well.
More to come...