Fire troll

A fire troll was a large giant that was immune to fire, and vulnerable to cold, the opposite of a typical troll.

Description
Fire trolls were large beings, most standing over 12' (3.7 m) tall. They were, in general, very rare. However, trolls of this type could be found in volcanic landscapes. Their intelligence ranged from average to very intelligent, among those were fire troll shamans, both dangerous and magical.

These trolls were thick-limbed humanoids, with deep red skin. Their eyes were sunken into their sockets, but were clearly there, due to their luminous yellow glow. The trolls' hair resembled fire, disorderly with streaks of orange and yellow, whereas their claws and teeth resembled fire-blackened steel. They were surprisingly good at swimming; though they stayed away from water, they often waded in thick magma. They mastered survival skills in volcanic lands, could climb up steep cavern walls, and possessed low-light vision spanning up to 300' (91 m).

Behavior
Such trolls enjoyed swimming and climbing in their natural environment. They were always hungry, but were never distracted by food dropped by fleeing prey, preferring to land the kill. Cunning and intelligent, they were known to make long-term strategies to overtake certain regions. They loved treasure and magical items that could resist extreme heat.

Trapping
Fire trolls were smarter than typical trolls, and were experts at setting traps and laying ambushes for unsuspecting prey. For adventurers willing to travel to such areas, they could be surprised by these trolls leaping out of magma pools, in which they'd been previously submerged. Adventurers, as well as being surprised, could be splashed by globs of burning hot magma. Some trolls even threw the scorching globs at foes, setting alight adventurers' equipment and their bearer alike.

Natural combat
Despite their thick limbs, trolls of this type were incredibly agile and struck with lightning-fast reflexes and attacks. They generally fought with a combination of clawing and then biting several opponents at once, due to their large size.

Fire trolls chose not to use weapons, as their dark claws and fangs were deadly enough. Holding a weapon would only slow down the troll's rapid attacks.

Resistances and immunities
As with most trolls, regeneration made combat a lot easier. In their preferred climate, they would regenerate even quicker than usual. To adventurers' further dismay, fire trolls could regenerate at more than triple the standard rate if submerged in magma. To even further throw off adventurers, fire trolls were immune to acid-based attacks. Trolls were known to be very weak to fire and acid, which were required to slay them. It seemed somewhat obvious that magma-wading fire trolls were immune to fire, but not at all obvious that they were also immune to acid. Thus, adventurers who slew a fire troll would think it logical to end its life with acid, but the troll would get back up and start attacking again. This made fighting fire trolls almost impossible for those without knowledge of fire troll immunities. For all these reasons, fire trolls were incredibly feared, and were as challenging in combat as some dragons.

There was one threat to the seemingly unstoppable fire troll, and that was by the ordered combination of cold, then moderate electrical damage or high physical damage. Cold attacks would damage fire trolls doubly, and, if reduced to unconsciousness, they would seem lifeless. However, the troll would thaw out and begin fighting again. However, if the lifeless body of the troll was struck by electric damage or high physical damage, it would die permanently.

Corrosive blood
The large, hardened limbs of fire trolls were hard to severe, unless a weapon was vorpally enchanted or incredibly sharp. Trolls, of course, could reconnect and regenerate such limbs. The blood of fire trolls was very corrosive to metal, thus causing weapons able to draw blood to simply melt away.

Society
Fire trolls mainly dwelt in volcanically active regions, preying on races of the Underdark or Deepearth. Here, they acted alone, or formed small family-based tribes. Males were the dominant sex, though there weren't any notable differences. Leadership was established by combat. Trolls never died in this way, as they could regenerate after being in a downed state. The tribal chieftain led hunts and set traps, and also got the first choice of loot from plundered neighbors.

Only females could become shamans and commanded a huge array of magic; they were second-in-command in fire troll tribes. They could cast incredibly potent spells from the spheres of chaos, combat, divination, elemental (fire, earth), necromantic, and sun. Rarely, a shaman could become a witch doctor, combining the power of both clerical and wizardly spells.

Fire troll females could give birth every eight years, with the single babe being able to mature in the same time. Such a fire troll could live up to 600 years of age.

Ecology
Being the top predators of their environment, they could go for months without food. They chose to prey on giant striders and firenewts. They also occasionally preyed on fire giants. They would be willing to leave their fiery domains to hunt weaker humanoids, such as drow and svirfneblin, down dark and cold corridors. Fire trolls relished such flesh, considering it a great delicacy.

Fire troll blood was used in fire and acid spells, as well as used in substances for its strong metal-melting properties.

History
It was unknown how fire trolls came to be. The sage Elminster, however, noted that they were a new form of troll, thought to be created by fire giant sorcerers. This seemed possible, as fire giants were opposite to their frost giant kin in terms of resistances and abilities, the same as fire trolls were to their kin, particularly ice trolls. These fire trolls would have been used as servants and guards for such fire giants. The fact that fire trolls later hunted fire giants for sport, and to show they were the masters of volcanic regions, could have been evidence for this.

Appearances

 * Video games
 * Baldur's Gate II: Throne of Bhaal • Icewind Dale II