The Four Horsemen

Overview
Summary
 * 1) Destroy Madruk Dhuum.
 * 2) Destroy Thul Za Dhuum.
 * 3) Destroy Ghozer Dhuum.
 * 4) Destroy Kazhad Dhuum.
 * 5) Return to Reaper of the Chaos Planes for your reward. to the Reaper [sic]

Obtained from
 * Reaper of the Chaos Planes in The Underworld

Requirements
 * Clear the Chamber
 * Take Restoring Grenth's Monuments quest and free the Reaper of the Chaos Planes by killing the Terrorweb Dryders around Grenth's statue in the Chaos Planes

Reward
 * 10,000 XP

Dialogue
 * "Before the time of Grenth, when death was ruled by a cruel and unjust god, there stood a tower and a throne on this very plain. But Grenth rose up and destroyed the one called Dhuum and shattered down his tower, leaving only these storms of chaos as a reminder of the power that once held dominion here.


 * My vigil over these lands was broken for a time, and I can feel a resurgence of the old taint. Four horsemen approach, riders of Dhuum. Destroy them before they can reclaim this place and throw the underworld into chaos!"


 * Accept: "I will defeat them!"
 * Reject: "I want no part in this."

Reward Dialogue
 * "With the Dhuum riders destroyed, I will see to it that the old taint does not gain dominion over this area again. The underworld will rest safely in the hands of Grenth."

Walkthrough
Four separate groups will spawn along the northern edge of the Chaos Plains and make their way toward the Reaper of the Chaos Plains. Each group will consist of one Horseman (Ghozer Dhuum, Kazhad Dhuum, Madruk Dhuum or Thul Za Dhuum), three Terrorweb Dryders, and one Skeleton of Dhuum.

The two groups of Ghozer and Khazad will merge about a full radar circle to the east of the Reaper, and the groups of Madruk and Thul Za will do the same about the same distance to the west. Then the two combined mobs will approach the Reaper from the east and west simultaneously.

Fighting next to the Reaper may not be the safest approach, as you will be surrounded and severely outnumbered. Splitting your team into groups and intercepting the monsters before they reach the Reaper may offer a better chance of success.

However, rather than splitting your team in half, consider sending a single tank to occupy one side while the rest of your team handles the other. The tank must be immune to enemy spells, as the Horsemen have Power Block, Cry of Frustration, Diversion, and Drain Enchantment. If the tank can't survive the Skeletons of Dhuum on their own, then a healer can support them.

Trivia

 * The concept of the Four Horsemen of the Apocalypse has its source in the Christian Bible, Revelation 6:1–8. The usual interpretation of this account identifies the horsemen with the ideas of Conquest, War, Famine, and Death.  The popular contemporary interpretation replaces Conquest with Pestilence.