Villages huddle int he frozen wastes of Vorostokov. Nomads wander the burning sands of the Amber Wastes. Tiny homesteads struggle to beat back the cyclopean forests of Verbrek. Life for the people of these communities is a daily struggle against unforgiving terrain. Their clans need hunters, warriors, and protectors, and the most powerful of these is the barbarian. Lone barbarians can also be found in other lands, where they live as solitary hermits or mountain men and avoid the noise of civilization. Among the monstrous races, barbarians are believed to be relatively common among lycanthropes and the larger goblinoids.
Barbarians respect physical prowess above all else; they eschew practiced combat techniques and "dirty tricks" of the fighter, seeking to win their battles through sheer force. Any education a barbarian receives likely comes from folktales heard at an elder's knee, so most barbarians are intensely superstitious. The Voros of Vorostokov, for example, believe that written words inherently contain evil magic.
The folk of more "enlightened" cultures view barbarians as uncouth at best, drunken berserkers at worst. Tales are whispered of unsuspecting travelers who fell afoul of inbred barbarian clans, who could sell the pelts of anything they could catch. Barbarians usually adventure to test their might, to gain power, or to protect their lands and family.
Weakness
Barbarians of Ravenloft can't voluntarily end their rage prematurely. If no opponents are left standing, the barbarian may attack unconscious foes or even his own party members if they appear threatening, until his rage runs its course. Attacking in this fashion may call for a Powers Checks at the DM's discretion, as the Dark Powers attempt to use the barbarian's gift for battle against him.
While barbarians may ostracize a coward, making it unlikely at best that they easily give in to fear, they're overly superstitious, which can lay them open to greater harm from Horror and Madness. If the barbarian must make a save for a horrific scene caused by, or a terrible experience linked to, arcane magic then they have disadvantage on the roll. Those barbarians from a society that accepts divine magic aren't affected in the same way, though barbarians from tribes with no divine spellcasters may be subject to disadvantage in the same situation.