Boreal Troll (Fey)--Montporte Dungeon Campaign Critter
Armor Class: 0 
Hit Dice: 8
Attacks: Clawed Hands x 2 (1d4); Bite (1d8)
Saving Throw: 8
Special: Regeneration; Cold Resistance; Sunlight Vulnerability
Challenge Level/XP: 9/1100
Boreal trolls are fur-covered humanoids, 12-15' tall. They are fey and live in the boreal forests of the plane of Umírající. They are occasionally found on the plane of Aarde (the plane of Montporte), looking for humans to devour. Boreal trolls are loyal to the Winter Court of the fey.
COMBAT: Boreal trolls are surprisingly agile in combat and are able to attack three times per combat round (two claw attacks and one bite). Because of their regenerative ability, they rarely back down from a fight.
REGENERATION: Boreal trolls instantly begin to regenerate when wounded, healing 1d4 points per round. No matter how battered or burnt their bodies may be, they will eventually regenerate. The only way to ensure that a boreal troll stays dead for good is to kill it and then destroy every part of its body with acid.
COLD RESISTANCE: Boreal trolls are immune to natural cold and gain +2 on their saving throws versus cold-based magical.
SUNLIGHT VULNERABILITY: Boreal trolls are vulnerable to full sunlight and will turn into a lichen covered tree trunk if exposed to the direct sunlight. They remain in this state for 40 years and then revert back to their troll state at midnight on the Winter Solstice. They maintain their regenerative ability, even as tree trunks.