Hellrock

Hellrock was a corruptive substance and living plague created by the Red Priests using the Elementium that fell from Deathwing during the Hour of Twilight.

It resembles a red coloured rock with streaks of orange and black running through its matter that resemble veins. The material slowly weeps a liquid substance resembling magma or blood and cools to form more Hellrock after several hours.

It is hot to the touch and incredibly durable and difficult to destroy.

The name Hellrock is a misnomer as the material itself is metallic, but the name originates from the rough and erratic patterns it grows into that resemble rock formations.

Effects
The most insidious property of Hellrock is that it feeds and grows upon the touch of any living creature. Upon touch, the creature becomes 'infected' and will slowly be encased in the substance as it grows around them, eventually consuming the host or trapping them within a thick carapace of the substance.

Beyond a certain point of infection, the host will begin to act against their will, or appear to fight an outlying force for control over their actions. This force became stronger the closer the afflicted moved towards Blackrock Mountain. Red Priests were immune from the effects of Hellrock, but this was not due to any special effects on their part but the favour of The King Beneath the Mountain. Those who failed him or attempted to leave the Priesthood were transmuted into pure forms of Hellrock and forced to serve.

Hellrock was shown not to affect the dead, and would affect the undead in a different manner to the living. While the living creatures were encased within Hellrock and only fully transmuted slowly over time, this transmutation began immediately with the undead. Their bodies would be replaced with the substance and could be made to shatter outwards in a violent explosion, acting as infectious detonations to any living they were in combat against. This was witnessed only once before the King's death, with the made-undead Flying Gang member, "Torch".

Curing the Affliction
A cure was discovered by several prominent Alchemists during Hellrock's existence. Unfortunately the cost inflicted upon the afflicted to cure them was so great that many hesitated before undertaking its effects.

As Hellrock was as much as mental affliction as a physical one, a powerful memory was to be selected from the user to focus upon, drawing the Shadow magics into it. From there, a delicate and powerful combination of purging reagents were given, drawn from Arcane, Druidic and Holy sources, all administered to the patient at the same time.

Once the cure was given, the purging agents removed Hellrock's influence from the host entirely, freeing them from its grasp and returning their bodies to their full control and restoration. However, the memory chosen, and all feelings surrounding it, was also entirely purged from the afflicted. This has so far been found to be unrecoverable.

A liquid form of the cure was discovered by Vyrona "Robes" Swiftshade, using the thousands of memories and sacrifices pulled from an alternate future where the denizens of Azeroth could not stop the Hellrock plague. This cure became a necessity during the Battle of Blackrock Mountain and prevented the assembled army from being immediately subsumed by its influence.

Destruction
After the Battle for Blackrock Mountain and the death of Duncan Brightfist, all traces of Hellrock were scoured from Azeroth and no remaining traces of the substance have yet been found or recovered. The remaining infected were either cured or disappeared entirely, depending on the level of infection they endured.