New Plague
From WoWWiki
The New Plague is the Forsaken's altered version of the powerful Plague of Undeath that led to the creation of the Undead Scourge. The Plague of Undeath had the effect of transforming normal humans into mindless undead in the service of the tyrannical Lich King. Some members of the Forsaken, including their queen Sylvanas Windrunner, were once pawns of the Lich King, but were later freed. The Forsaken's aim is to create a new plague that would annihilate the Scourge itself, and perhaps later their living enemies as well — and raise them to replenish and expand their own numbers.
The Royal Apothecary Society, the alchemical experts of the Forsaken, have been working on various ways to use various parts from creatures living in their sphere of control as well as agriculture grown in the Tirisfal Glades and the Hillsbrad Foothills to create powerful toxins. The nearest brush with success yet seen involved pumpkins from the Solliden Farmstead in Tirisfal. When tested on a Scarlet Crusader held captive in the Brill Inn, it brought about transformation into a ghoul, only to cause true death seconds later.
The use of the New Plague on humans has thus far been only partially successful. While it kills the victim, it doesn't bring the human back after death as a new Forsaken. Other problems remaining include distribution; the Royal Apothecary Society is searching for a way to effectively spread their new plague, so that no living thing remains on the entire planet...leaving all of Azeroth as one big plagueland, ruled by the Forsaken. Sylvanas' initial plan is to wipe out her immediate enemies — the Scourge and then the Alliance, and raise them again to her cause.
The Royal Apothecary Society, a sect of Forsaken alchemists, are fanatically loyal to the Dark Lady. Recently, the alchemists were assigned by Sylvanas to a project to create a master Plague, similar to Ner’zhul’s, to wipe out the living races as well as the Scourge. The apothecary Faranell heads the project, constructing a New Plague to wipe out all of humanity and the Forsaken’s nemesis, the Scourge. So far, the Society has not yet produced results. Since the world at large refuses to accept them as people instead of undead, they will continue their dark designs to eliminate all non-Forsaken life forms on Azeroth. However, at this point their Plague kills only humans, and doesn’t affect the Scourge at all. The Royal Apothecary Society believed that their usefulness to the Dark Lady may be coming to an end. They were afraid that if they could not finish their master Plague, they might find their Society disbanded. Due to repeated failures by the society to make a New Plague, Sylvanas started recruited necromancers to find other means of raising slain enemies, into her cause.HPG 153-154
Castillian was responsible for delivering spores which helped lead to the finalization of the New Plague.
All though located in a remote town, Hierophant Theodora Mulvadania and Warlord Goretooth seem to have heard rumours about the new plague.
Infiltrator Marksen seems to know what the Forsaken is up to.
Quests that refer to the new plague
- Battle of Hillsbrad
- A New Plague
- Hints of a New Plague?
- Delivery to Silverpine Forest
- A Recipe For Death
- Journey to Hillsbrad Foothills
- Elixir of Pain
In Wrath of the Lich King
The towns of New Agamand and (to a lesser extent) Vengeance Landing in the Howling Fjord and the town of Venomspite in the Dragonblight are the Forsaken's major centers for production of the "New Plague" in Northrend. After several failures in Howling Fjord, the apothecaries of New Agamand send a sample of the perfected plague, known as the "Forsaken Blight", to Venomspite. The Forsaken Blight, combined with a reactive agent, is powerful enough to turn its victims (or at least the undead ones) into shapeless piles of goo. In the quests 
[72] The Forsaken Blight and You: How Not to Die and [72] Emerald Dragon Tears, Horde players are sent to find said reactive agent (the ectoplasmic residue from the ghosts of Arthas' troops on the Forgotten Shore) and a vessel to contain them (tears of green dragons from the Emerald Dragonshrine). Before delivering the plague to Doctor Sintar Malefious in Agmar's Hammer, the player must drive a Forsaken "blight spreader" catapult from Venomspite to an area of the Carrion Fields outside of Wintergarde Keep, right in the shadow of Naxxramas, to test this new blight on the Scourge ( [72] Spread the Good Word). It appears that the forces of the Scarlet Onslaught are immune to this plague, as indicated in the failed test against an Onslaught Prisoner in [72] Blighted Last Rites. Amusingly, Alliance players also accidentally create the Blight in the quest 
[71] Absholutely... Thish Will Work!, which entails a drunken gnome alchemist sending the player to give an 'antidote' to a vrykul prisoner, which causes him to dissolve into a pile of goo. Upon completion, the quest giver says, "Huh? Well that sucks! Darn, I made thingsh worsh. In fact, I think I perfected their plague for them ...hic!"
The Forsaken Blight's most despicable use occurred during the Battle of Angrathar the Wrathgate. After Dranosh Saurfang was slain by the Lich King while he and Bolvar Fordragon confronted him, Grand Apothecary Putress arrived on the bluff overlooking the battlefield with several blight spreader catapults. Serving the dreadlord Varimathras, who had launched a coup against the Dark Lady and taken control of the Undercity for the Legion, Putress launched the Blight against both the Scourge and the combined Alliance-Horde forces. The attack resulted in the death of Highlord Fordragon, the near-total destruction of the combined army, and even weakened Arthas himself, who retreated back into Icecrown Citadel.
The Forsaken attack is considered by the Alliance to be outright treachery on the part of the Horde, and the coup by Varimathras gave King Varian Wrynn an opening to purge the Horde from Lordaeron and retake the city for the Alliance. King Varian leads Alliance forces in a battle for the Undercity to avenge Bolvar and retake Lordaeron, while the Horde launches an attack on the Undercity to reclaim it from Varimathras.
