>Satanist shills
Surprisingly rare, but they are found on boards. Usually they're just government types (intel agency, classically). Often they use the technicality that they're 'pagan' and not 'satanist' (despite using things like the pentagram and using really obviously satanic things).
Classically, references to H.P. Lovecraft will be made. They usually have a disdain for a stereotyped version of Christianity.
Surprisingly or unsurprisingly, they can actually just be beaten with plain reasoning (but you will need extensive knowledge of both history and religion as often they will try to appeal to extremely obscure technicalities, such as the history of Sumatra, Babylon, Ancient Egypt and more).
In one case it was argued Christianity was responsible for most wars during the middle-ages to current history, which is a common belief.
Ignoring the fact that the so-called 'Christianity' in question clearly didn't follow any biblical teaching of 'turning the other cheek' and 'those without sin casting the first stone', I actually challenged what research had been done to prove this? Naturally, of course: none.
They cited a few cliche example wars (Crusades, namely), but it's worth noting history has had thousands of wars. So instead, I proposed a challenge (blind to the answer) that I bet if I tallied the 'cause of war' (using as many Wikipedia articles as possible) from 1100s to 1700s (covering a key period prior to the introduction of secularism and naturalism post 1700s), I would found more were attributed to other causes.
This is ignoring the fact religion might have been blamed as a 'partial cause' or a scapegoat (I treated partial cause and suspected scapegoats as if they were the actual cause, except when it was clearly a scapegoat), I manually skim-read over 1000 wikipedia articles on war.
Much to their rage, I found that actually, TRADE, ECONOMICS and LAND disputes were the major drivers (trade being the biggest one). I also discovered on war was sparked over someone losing a cockerel fight (yeah, you read that right).
Religion accounted for about 40% (this includes treating 'partial causes' and 'suspected scapegoats' as full causes, so it's likely less than this), but trade was nearly 50%, with the last 10% being political wars and misc. causes.
The person in question became extremely stroppy and stopped talking to me (despite declaring 'satanism was the pursuit of truth' - apparently only truth that is convenient to it's own objectives).
Sure, Wikipedia might be incomplete, or inaccurate, but a manual survey of over 1,000 wars is better than a statement based on gross generalisation, oversampling (EG small sample size projected to have a much larger influence) and popular opinion.
And such research can be double-checked, revalidated.
In practically every instance of refuting a satanist I've always found they become emotionally unreasonable, and will then start attacking or ignoring.
Truth and facts always win out, no matter what the circumstances. I just happened to know enough about history to already have had an inkling it wasn't the biggest cause of war.