Many years ago, the former king of the powerful spider empire Azjol-Nerub was none other than Anub'arak, now a senior commander of the Scourge. He had fought bravely against the Lich King's forces during the Spider War, but, sadly, he had ultimately fallen in battle. Ner'zhul soon resurrected him as a Crypt Lord of the Scourge.
After that,
Crypt Lord Anub'arak naturally turned on the ancient spider empire. In the end, he became its conqueror, destroying the vast underground empire he had once sworn to protect with his life.
Not long afterward, on the Lich King Ner'zhul's orders, he led a contingent of elite undead warriors into the Nerubian Ziggurat, now known as Naxxramas. Little by little, they transformed it into a colossal, terrifying war machine: the floating fortress Naxxramas!
Inside Naxxramas, tens of thousands of the Scourge's elite undead often gathered. Here, demons ran rampant, chaos reigned, and filth covered the ground... The Lich King's mighty will permeated every corner, controlling everything within! Dark magic kept the enormous fortress effortlessly aloft, while all manner of terrible plague weapons and superior air power were concentrated within. This made Naxxramas the Scourge's most powerful strategic deterrent, beyond question.
So far, across the entire Eastern Kingdoms, only Dalaran—with its powerful anti-air magic—had given the undead any reason for concern. No other individual force had the ability to oppose the Scourge fortress Naxxramas! Not the Gryphon Riders of Aerie Peak, not the gyrocopters of Khaz Modan, and not the Dragonhawks of Quel'Thalas!
And that was precisely what had given the Lich King and a certain Dark Lord the confidence to wipe out Lordaeron in one fell swoop.
But...
More than half a month had passed. For various reasons, the Scourge had been forced to slow its final offensive in Tirisfal Glades. The undead