Barbarian

For some, there is only rage. In the ways of their people, in the fury of their passion, in the howl of battle, conflict is all these brutal souls know. Savages, hired muscle, masters of vicious martial techniques, they are not soldiers or professional warriors—they are the battle possessed, creatures of slaughter and spirits of war. Known as barbarians, these warmongers know little of training, preparation, or the rules of warfare; for them, only the moment exists, with the foes that stand before them and the knowledge that the next moment might hold their death. They possess a sixth sense in regard to danger and the endurance to weather all that might entail. These brutal warriors might rise from all walks of life, both civilized and savage, though whole societies embracing such philosophies roam the wild places of the world. Within barbarians storms the primal spirit of battle, and woe to those who face their rage.

Barbarians excel in combat, possessing the martial prowess and fortitude to take on foes seemingly far superior to themselves. With rage granting them boldness and daring beyond that of most other warriors, barbarians charge furiously into battle and ruin all who would stand in their way.

Barbarians in Azeroth are mostly found amongst the Horde and a little bit amongst the Alliance (ironically humans, night elves, and worgen). They have the primal spirit of battle within them and are powered by rage. An integral part of the Warrior class in WoW. However, the Pathfinder RPG is much more than that, splitting the WoW Warrior into fighter and barbarian.

Amongst the Alliance
Barbarians are found in the civilized races of Humans, Night Elves, and Worgen. Much more amongst the Worgen than the other two of the three. Infact, King Varian Wrynn of the humans has at least five levels of Barbarian reflecting his time as a gladiator amongst the orcs. Conversely, those few Graymane Worgen who embraced  their animalistic and savage nature out of despair at being changed into worgen have become barbarians. And as for the Night Elves, many fought in the in the first battles of the War of the Ancients as barbarians against the Highborne and the Burning Legion. Human barbarians come from the outskirts of what is left of the Empire of Arathor and are found in Stromegarde, as civilization in the Arathi Highlands are on the brink of anhilation.

There are few barbarians amongst the Gnomes, the Draenei, and the Dwarves. The last having more than the gnomes and the draenei, especially with the inclusion of the Dark Iron clan. As for the Pandarens of the Alliance? A majority of them have advanced beyond all that foolishness of being barbarian.

Amongst the Horde
Orcs are the prototypical barbarian race as far as the Warcraft world is concerned. Each of them can be thought of as green Conans or green Jongors with a pronounced underbite. Almost all orcs that do battle are barbarians. This is not to mean that orcs lack civilized weapon arts (they don't), it just means that most orcs fight according to their lifestyle as barbarians.

Most orc barbarians are ironically from the Warsong, the Bonechewer, The Black Rock, and the Stormreaver clans. Most orc fighters come from the Frostwolf and Thunderlord clans. Trolls also make up a good part of the barbarians of the horde. Finally, there is the Forsaken. Most of the fighting forsaken are barbarians.

There are no barbarians amongst the Blood Elves, they have been civilized for just too long. As for the Goblins? Goblin culture is built around trade and money, which is mystifying to a barbarian. There are few barbarians amongst a culture that is so decadent. Then there is the Taurens. With the development of the Sunwalkers, the Tauren Paladin, the Taurens have taken a large step towards Civilization. With the founding of Thunderbluff in Mulgore, it was another huge step. The Taurens have begun to develop their own weapon arts, which is another step. Barbarians amongst the Taurens are becoming a dying breed. There are still many, but as young calves are studying the weapon arts and the shamanistic and druidical ways of the Tauren become much, much more developed, the Barbarian amongst the Tauren are slowly dying out.