Imagine a small chunk of wood. At the end of it flickers a yellow-red shape, casting a cruel light on you. Imagine the primal fear that tugs at your soul knowing that baleful glow can harm you, can kill you if it touches your skin. This is what a troll thinks when he sees fire. Fire is death. It is not warmth or comfort, it is pain and destruction and agony. Little wonder then that most trolls will hesitate to attack even when confronted with a simple torch. Now consider that there are some trolls who worship this deadly fire.
They can be compared to the death-cults humans are so drawn to; ritual murders and necromantic studies undertaken to cheat, or at least postpone, death. Their counterparts among trolls are fire-cults. It’s easier to recognize troll fire-cultists than human death-cultists: Fire-cultists are completed devoid of hair and covered with ritual scars. Yes, scars. Some natural philosophers will swear by their mentors’ souls that trolls cannot have scars because of their regenerative powers; this is usually true, but the fire-cultists have figured out how to get past that hurdle. Metal tools are heated until they are at least red hot, then the scar-patterns are traced upon the skin of converts by senior members. The first scarification ritual lasts about 36 straight hours. Those who try to recant their conversion become impromptu sacrifices destined to be slowly burnt to death.
Fire-cultists sacrifice a variety of offerings to their strange patron via immolation: Books, oil, cloth, animals, people. However, they especially seek to capture normal trolls alive and slowly roast them to death. Fire-cultists consider this to be the form of offering most pleasing to their master. They also don’t mind a bit of arson every now and then, especially when they’re leaving an area to find a new lair. Aside from the dangers of arson, their predation of common trolls also causes problems because it strengthens the power of local orcs, goblinoids, or ogres.
Despite all this, the strangest fact of the fire-cultists is this: Something has answered them. Fire halves the potency of their regeneration instead of negating it. Many a foolhardy adventurer or troll has charged against fire-cultists expecting a quick flaming victory only to find himself on the sacrificial pyre.
As for the identity of their mysterious benefactor none can say; the fire-cultists don’t even seem clear on that themselves. They general refer to their deity as “The Devouring Flame” or “The Fire That Ends The World” but sages have been unable to connect these titles to any known extraplanar powers.