Troll, War (CR 12)

Large Monstrous Humanoid
Alignment: Usually lawful evil
Initiative: +7; Senses: darkvision 90 ft., low-light vision, scent, Listen +11, and Spot +12

AC: 31 (-1 size, +14 natural armor, +5 breastplate, +3 Dex), touch 12, flat-footed 28
Hit Dice: 12d8+108 (162 hp); DR: 5/adamantine
Fort +13, Ref +11, Will +12
Speed: 40 ft. (30 ft. in breastplate)
Space: 10 ft./10 ft.
Base Attack +12; Grapple +26
Attack: Masterwork greatsword +23 melee or bite +21 melee or masterwork composite longbow (+10 Str bonus) +15 ranged
Full Attack: Masterwork greatsword +23/+18/+13 melee and bite +19 melee; or 2 claws +21 melee and bite +19 melee; or masterwork composite longbow (+10 Str bonus) +15/+10/+5 ranged
Damage: Masterwork greatsword 3d6+15/19-20, bite 1d6+5, claws 1d8+10, masterwork composite longbow (+10 Str bonus) 2d6+10/x3
Special Attacks/Actions: Dazing blow
Abilities: Str 31, Dex 16, Con 29, Int 8, Wis 15, Cha 10
Special Qualities: regeneration 9, SR 20
Feats: Alertness; Improved Initiative; Iron Will; Multiattack; Weapon Focus (greatsword)
Skills: Listen +11 and Spot +12
Advancement: By character class
Climate/Terrain: Any
Organization: Solitary, pair, or gang (3-9)
Treasure/Possessions: Standard (including masterwork greatsword and masterwork composite longbow [+10 Str bonus])

Source: Monster Manual III

Dazing Blow (Ex): The force of a war troll's blow can be overwhelming. If a war troll hits with a weapon or claw attack, the opponent must make a DC 25 Fortitude save or be dazed for 1 round. The save DC is Constitution-based.

Regeneration (Ex): Unlike with their lesser cousins, acid (not fire) deals normal damage to a war troll. If a war troll loses a limb or a body part, the lost portion regrows in 2d4 minutes. The creature can reattach the severed member instantly by holding it to the stump.

Unlike their troll kindred, war trolls are precise and methodical in combat. They trust their regenerative abilities to see them through a fight against even powerful warriors, so they focus their attention on spellcasters early in any skirmish.