So far the party thinks they might be from the Island of the Gods since they heard a rumour of the Island being illuminated, seen from accross the ocean. They also think that this group had something to do with the burning down of a small spice village close to Stormshire.
They know that they are responsible for the burning of one of thier "converts" and the church with him. They think there might have some relevence to them later seeing someone gathering up the ashes of the convert.
They seem to worship Fire or a God of Fire, but Ezekiel noticed that all of the magic cast at Bill (for pissing them off) was Elemental Magic and not divine. Ezekiel also thinks that a lantern was the cause of the intense magical fire that caused the temple to burn so hot.
The White Fire Elementalists were last seen leaving to the north of Diev.