Troll, Fire (CR 9)

Large Giant (Fire)
Alignment: Usually chaotic evil
Initiative: +2; Senses: darkvision 90 ft., low-light vision, and scent

AC: 22 (-1 size, +3 Dex, +10 natural), touch 12, flat-footed 19
Hit Dice: 10d8+80 (125 hp)
Fort +15, Ref +6, Will 4
Speed: 40 ft.
Space: 10 ft./10 ft.
Base Attack +7; Grapple +20
Attack: Claw +15 melee
Full Attack: 2 claws +15 melee and bite +13 melee
Damage: Claw 1d8+9, bite 1d8+4
Special Attacks/Actions: Rend 2d8+13
Abilities: Str 28, Dex 17, Con 26, Int 10, Wis 12, Cha 11
Special Qualities: Acidic blood, fire and acid immunity, fiery regeneration, regeneration 8, vulnerability to cold
Feats: Improved Bull Rush; Improved Natural Attack (claws); Multiattack; Power Attack; Track (b)
Skills: Climb +22 and Survival +14
Advancement: By character class
Climate/Terrain: Any warm
Organization: Solitary or gang (2-4)
Treasure/Possessions: Standard

Source: Dragon #199
Dragon Compendium Vol. 1

Rend (Ex): If a fire troll hits the same target with both of its claw attacks, it latches on and tears into him. This attack deals an additional 2d8+13 points of damage.

Acidic Blood (Ex): The fire troll's blood is highly acidic. Any weapon used to strike the troll risks exposure to this searing acid. The acid deals 1d6 points of damage. A DC 23 Reflex save negates this damage. The weapon's hardness does not provide any protection against this acid. Attackers who use natural weapons, such as an unarmed strike, must make this save or take the damage. This ability's save DC is Constitution-based.

Fiery Regeneration (Ex): The fire troll's regeneration ability draws on the energy available in areas of severe heat (110° F or higher). Under such conditions, the fire troll's regeneration increases by 4 points to 12 points per round. If any effect that deals fire damage targets a troll, its regeneration ability increases to 20 points for 1 round. If the troll is exposed to multiple attacks during the same round, its improved regeneration 5 duration remains 1 round.

Regeneration (Ex): Electricity deals normal damage to a fire troll.

Vulnerability to Cold (Ex): Trolls regenerate cold damage despite their weakness to it. If cold damage drops a fire troll to 0 or fewer hit points, it must make a Fortitude save (DC 15 + cold damage taken) or be frozen in place. The troll is helpless for 2d4 rounds. If further physical or electrical damage reduces it to -10 hit points or lower, its frozen body shatters into dozens of pieces, killing it.

Fire trolls are smarter than normal trolls. They prefer to strike from ambush, and whenever possible they exploit their immunity to fire and acid damage. A fire troll might wade into a stream of magma to leap out and attack passing travelers. Fire trolls use their Improved Bull Rush feat to knock foes into magma before diving in after them. Their love of roasted, burnt flesh makes this tactic their preferred method of fighting.

In areas of extreme heat, fire trolls prefer hit and run attacks to wear down their enemies. They know that softer creatures - as they call those vulnerable to heat - lose their strength and vitality when exposed to searing temperatures for extended periods. Fire troll spellcasters use dispel magic to tear away any defenses against heat attacks before a tribe closes for combat.

Fire Subtype

A creature with the fire subtype has immunity to fire. It has vulnerability to cold, which means it takes half again as much (+50%) damage as normal from cold, regardless of whether a saving throw is allowed, or if the save is a success or failure.