How to Succeed in War Without Really Trying
Common Knowledge: The Sovereigns of the world are civilized. Despite their often fractious debates among Vassals, their mortal worshipers, they stand for civilization and peace and justice. Of course, they all have their own idea on how those values are best served. The Sovereign of War says that the best way to have peace is to be so strong that none dare oppose you. The Sovereign of Trade says that binding people together with commerce will make war inconceivable. And so on and so forth.
The one thing they all agreed on was banishing the Dark Six from their halls.
Because The Dark Six are none of those things. They revel in the uncivilized. Violence, destruction, ignorance, passion, and all the things that the bloodless Sovereigns pretend do not exist in their "civilization."
While few actively worship the Dark Six, most people will offer a short prayer or small sacrifice to keep them sated. A sailor reveres the Sovereign of Trade, but he also murmurs a small prayer to the Devourer and throws a carved idol overboard to keep him sated for the trip.
Allies: The Blood of Vol believes that all gods are bastards, but they're willing to respect the Dark Six for being honest about it. Also, since both of them are far less respectable religions, there is a fair amount of commiseration between the rank and file than one would suspect due to their theology.
Enemies: The Dark Six isn't respected in polite society, but the worshipers of the Sovereign Host and Church of the Silver Flame take a particularly dim view of the Dark Six. Admittedly the Sovereign Host does a have a more complicated view on the matter, but they see a clear difference between keeping the Dark Six at bay with offerings and actively worshiping and promoting them. The Silver Flame doesn't even grant that measure of acceptance, saying that they need to be opposed at all levels.
The True Danger: Everything will be fine as long as the Dark Six are never allowed to rejoin the Sovereigns in their halls.