Historical centre of Diabolism on Golarion

[Callum Finlayson]

Was there somewhere (pref Avistan) where historically Diabolism was prevalent?

Obviously Cheliax currently, but I'm wondering about a few centuries (or millennia) prior to Aroden's little oops & the kerfuffle that followed.

[keftiu]

In Garund, one can look to both the extinct nation of Rastel and the current Bekyar culture for peoples who did a lot of work with fiends.

[Perpdepog]

There is also some evidence of Diabolism being present in the Jistka Imperium, or at least the worship of fiends. They were the originators of the fiend-infused golem, which requires a bound fiend--the creature's description indicates that devils were most often used for this purpose--for its motive force. I'm basing that on the fact that they have the same sorts of immunities devils have, and also use Hellfire as part of their attacks.

[The Raven Black]

The centers of power of House Thrune.
"The House of Thrune is an ancient noble house of Cheliax whose adherence to the infernal philosophy of Diabolism long predates the fall of Aroden."