Bray-Shaman

All users of magic must tap into the magical energies loosed from the Realm of Chaos, but Bray-Shamans use this energy in a natural, almost instinctual way. They are born knowing how to wield Chaos energy in its raw form like other Beastmen seem to know how to hunt, track, and kill. Therefore, Bray-Shamans need not study or undergo special training; they simply know.

One of the most important powers employed by these Beastmen is their ability to send their consciousness into the Realm of Chaos, there to converse with the Daemons and even the Gods they find there. They reach this plane by drinking themselves into a stupor and breathing the fumes of hallucinogenic plants thrown into the fires at the base of the Herdstone. Their ability to commune with the Gods ensures they are safe from attacks by the rest of the Warherd, since all Beastmen believe that harming a Bray-Shaman means utter annihilation at the hands of their foul Gods.

Bray-Shamans are physically similar to Gors. What separates them from others of their kind is the colour of their eyes. The colours signify which Chaos Power favours the Shaman: blue or yellow for Tzeentch, green or brown for Nurgle, pink or purple for Slaanesh, and bright red for Khorne (though Shamans of Khorne never cast spells). They typically dress in elaborate gowns or decorated hoods. Most carry staves (specifically Braystaves, see sidebar for details) and often banners decorated with scalps and bones.

The Bray-Shamans are an important part of the Warherd, serving as advisors to the Chieftain. More importantly, they lend their prowess to defending the herd and destroying their enemies. Some legends claim that Bray-Shamans can actually Spirit-Walk the Realm of Chaos, enabling them to directly commune with Daemons and, some say, even the Dark Gods themselves. From these journeys, dreams, and hallucinations, they can foretell the future.

Greater Bray Shaman
The Greater Bray-Shamans are among the most powerful of all Beastmen. Armed with the powerful Marks of Chaos, they can access the most dangerous magic. Combined with their potent combat abilities, they are some of the most powerful members of the Warherd.

Source

 * Warhammer Fantasy RPG 2nd ED -- Tome of Corruption (pg. 102-103).