"Barbarian" is a pejorative term typically assigned to groups of hunter/gatherers by those who consider themselves "civilized". This post specifically describes the "clans of men" in Calabria, and how standard Labyrinth Lord and similar classes fit within the "barbarian" or "noble savage" context.
"Barbarians" have a +2 penalty to their reaction roles when dealing with "civilized" people.
The clans each have a general territory they claim as their own. These territories are most often in rugged wilderness such as forests, mountains, remote costs or even small islands. Each clan has a totem animal. Totems include but are not limited to: bear, wolf, gryphon, eagle, deer, horse, badger, squirrel, boar, viper.
Most adult members of the clans (both male and female) are fighters. Spread of levels is similar to those of "civilized" cultures, with only a small percentage reaching the highest of levels. A chieftain might be 10th level or higher, with his sons typically also being among the highest levels in the clan.
Clan members have limited ability to assume "animal shape". For three consecutive days, once per month (usually centered on the full moon) members have the ability to assume the shape of their totem once per day. The duration of the transformation can be as long as four days, but each day the member does not transform back to human, there is a cumulative 25% chance that they will forget their humanity, and remain permanently in animal form. (Remaining in animal form for four whole days automatically results in permanent transformation)
Clan members in their home territory or similar terrain gain several advantages. Due to their close ties to their animal totem, clan members are only surprised on a 1 in 6. With two turns of mental preparation they can also perform the following as a thief of half their level (round up).
Find Traps (snares, pits, etc...)
Detect Smell (same chance as Hear Noise)
(These abilities typically don't work in environments very different from their home territory, as they are unable to discern sounds/smells/traps elements that are out of the ordinary for that environment. A clansman of a forest environment would be displaced underground or in a city. Certain strong smells, such as orc or their totem animal, might be detectable regardless of environment).
Fighters are limited to medium or light armor (nothing more than 40 pounds of armor).
Thieves can not pick pockets or locks, but perform other thieving abilities as a thieves 2 levels higher
Each clan has a resident Druid. However, Druids are respected equally among all clans. Druids are the arbiters of the clans, and a ruling by a Druid is respected equally among all clans. A Druid can demand the cessation of combat between two clans for up to three days, but such cessation can not be demanded again for one year by any Druid.
Bards are identical to Druids, with the following exceptions:
They must use a chosen instrument to cast their spells.
Casting spells takes two full turns
They do not have the Druid armor or weapon limitation (but do have the clan armor limitation)
They get Charisma bonus to casting spells (targets must subtract Bards charisma bonus from saving throws)
"Witches"are anomalies in their clan. They are considered "touched" by the gods, and typically live apart from the clan.
They can create "fetishes", potions, and charms. These items can be used one single time. They can be used by the Witch, or given away. They are only effective as intended if they are given freely by the witch, as in most cases they must be made specifically for the recipient and the target. If taken against the will of the witch, use of the items can have unpredictable results. These items can match the effects of any Druid, Cleric, or Magic user spell of level equal to the Witch.
Witches are zero level for fighting purposes.