Few forces have devastated the world as badly as plague. Though magic is partially to blame as well, the Plaguelands of Lordaeron are a testament to the ravages that disease can bring to the world. While other people perpetually bemoan their dead and portray themselves as the sole victims of the pestilence of the age, the stoic races of the Horde soldier on, accepting life's misfortunes without feeling a need to complain. Unlike others, the wise races of the Horde realized that the plague must be fought intelligently and skillfully, through knowledge and not with wild sword strokes. After long and careful deliberation the Horde formed a new order of druids, the plagueshifters, who were charged with reclaiming the Plaguelands and other stricken areas for the Horde.
Plagueshifters fill a specialized role, one typically taken by tauren druids, who are willing to leave Kalimdor and walk in far lands. To become a plagueshifter, one must risk exposure to the deadliest diseases and poisons, and learn to master them. It's a dangerous profession, but just as the mastery of sharp steel has its rewards, so too does the victory over the most insidious enemies of the natural world.
The plagueshifter's body and mind are strong enough to resist the effects of poison, disease and similar effects. The plagueshifter can recognize any natural or magical disease. The plagueshifter's mystical forces protect her not only against disease, but also against the creatures that carry them.
The plagueshifter can enchant four stones and place them in a square to protect an area from harm. All vermin are unable to enter or exit the area, likewise natural diseases are also barred. All diseased creatures within the area do not spread their illness, nor do they suffer the disease’s effects. The effects last for as long as the plagueshifter cares to leave the stones in place, other effects and creatures cannot move them.
Plagueshifters are capable of summoning creatures to their aid. They can summon strange creatures called white hounds, that can understand the plagueshifter's speech and obey to the best of their ability. White hounds can cure by touch, and their bite releases divine magic.
They are also able to summon water elementals. The elemental must stay in fresh water, and cannot venture far from where it was summoned. All waters near the elemental are made free from corruption and disease and are drinkable, even the polluted filth of the Eastern Plaguelands is cleansed. The elemental remains until the plagueshifter dismisses it. The water can be polluted again.
The plagueshifter may plant a magical garden that yields an incredible bounty of fruits, grain, and nuts. Even normally carnivorous creatures may eat from this garden and be content. Regardless of pestilence, blight or frost, the harvest cannot be diminished. However, fire (or flooding with befouled water) destroys the garden.
The plagueshifter can use purify food and drink as a spell-like ability at will. The plagueshifter can touch a living creature and infect it with a short-duration, low-grade fever that puts it into a berserker state.
Plagueshifters in the world
Most plagueshifters are members of the Horde, typically orc shaman who live near the Plaguelands and tauren druids who traveled to Lordaeron and trained themselves to battle the Scourge. They're a relatively recent addition to the Horde's druidic orders, so their influence has not been felt in the world, and the Scourge and the Forsaken haven't taken any notice of them - yet. As it is a horde-conceived notion, all current plagueshifters are members of the Horde.
However, it is important to note that any race has the potential to become a Plagueshifter, as long as they meet the prerequisites to become one. (That is, they must have the ability to cast Remove Disease as a divine spell, have a certain level of the heal skill, and knowledge of nature.)
In World of Warcraft
The combined efforts of the Earthen Ring, Cenarion Circle and Argent Crusade managed to heal down the Western Plaguelands. Rayne, Rimblat Earthshatter, Mulgris Deepriver, and Adrine Towhide could be seen as plagueshifters.