The Four Horsemen were the most feared of all the scourge lords. The Archlich Kel'Thuzad considered them his greatest creation.
The Four Horsemen are damned souls, shackled in anguish for eternity. They would be powerful allies against the Burning Legion, but few would pay the price for such power.
<Highlord Mograine pauses for a moment before continuing.>
Perhaps there is one... a fallen general of the Horde.
Seek out the resting place of Nazgrim and call him to undeath. He will answer.
General Nazgrim was one of the finest warriors this world has known, and his loyalty was unsurpassed... even for an orc.
He deserves the peace of death, but this world cries out to be saved. The time for rest is over...
Come, Deathlord, let us do this unholy act... and call Nazgrim into the arms of the damned.