We covered the ancient aqir and their qiraji descendants last week. What we didn't really cover was the group of arthropods who headed north, enslaved the Ulduar region's tol'vir and founded ancient Azjol'Nerub. From the time of their expulsion from the central part of the ancient supercontinent of Kalimdor by the Gurubashi and Amani trolls, to their defeat and subordination of those tol'vir, and up to their recent near-total destruction by the Scourge during the War of the Spider, the aqir offshoot calling themselves nerubians have existed apart from their southerly kind. While the qiraji serve C'thun, the nerubians seem wary of the Old Gods and their Faceless Ones, even when gripped by the Lich King's undeath.
Furthermore, while many nerubians ended up in the service of the Lich King, forcibly resurrected by him, it's telling that the nerubians were immune to the plague of undeath and waged a war against him for over a decade, only losing when they found themselves trapped between the servants of the Old Gods and the dreadlords that at the time served as the Lich King's advisors and jailors. Their immunity to the plague did not confer immunity to undeath when directly raised, and so Anub'arak, last king of the nerubians, ended up a slave like much of the rest of his race.
As of the pre-Cataclysm world, nerubian undead can be found in the plaguelands serving alongside the Cult of the Damned as well as in Northrend itself, while the battered and hateful remnants of the empire of the nerubians are so desperate that they'll accept help from the races of the Alliance and Horde.
We now know that the aqir, when broken by their war with the troll empires, split into two main groups, one descending south until it reached the resting place of C'thun and one going north to the region today known as Northrend. Before the great Sundering that split Kalimdor in half, these aqir refugees were already undergoing the process that would render their race distinctive from the aqir/qiraji that they had been and were related to. For some reason, their race altered, and while the qiraji tended more towards semi-humanoid shapes and the silithid ancestors were more waspish or insectoid, the proto-nerubians would begin changing in a way that led them to be more arachnid in appearance, although their massive crypt lord rulership is more akin to scarabs. Since we now know that the ancestral nerubians waged war on and ultimately defeated and enslaved the tol'vir of Northrend, using them as living shock troops, it's possible that the use of the scarab form (seen clearly in Uldum and Ahn'Qiraj, two sites connected to the tol'vir) was a debased form of cultural transference and could have even been deliberate on the part of the nerubians to better control their tol'vir living weapons.
However it happened, we know little about the nerubians between their conquest of the tol'vir and entrenchment in what would be known as Azjol-Nerub and the War of the Spider. We know they weathered the Sundering relatively untouched. We know that while C'thun harnessed their former kinfolk in AQ, they avoided contact with the faceless ones and the Old Gods as much as possible. Their culture divided into its current caste system, with ancient queens giving birth to the scarab/spider hybrid spiderlords, ruling over common workers, warriors and even the semi-humanoid vizier caste, which bears some similarities to qiraji prophets and seems to fill a similar societal role (minus the mad proselytizing for the Old Gods). While they weren't servants of the ancient evils like Yogg-Saron, they were still descended from the ancient aqir, still the ones who came north and enslaved the tol'vir and stole their cities for their own use. Still xenophobic and cruel, still carrying the ancient hate for other races that led them to war with the trolls so long before. It would be that hate that would ultimately doom them.
This eternal cycle came to and end with the arrival of the Lich King to Icecrown Glacier. Although, to be fair to them, the nerubians not only fought against the transformed Ner'zhul and his demon jailors, they actually managed to balk them for a solid decade, keeping them occupied and buying time for the other races of Azeroth to rebuild after the chaos of the Second War and the events that took place beyond the Dark Portal itself. Had the nerubians managed to somehow suppress their loathing for others and ask any of the other races of Northrend for help, perhaps they could well have succeeded in their war with the Lich King. Then again, who would they have asked that would have listened to them? The Drakkari trolls? The wolvar? The oracles? The tuskarr, the tauren, the vrykul? Even without such aid, their natural immunity to the plague of undeath and the leadership of proud and powerful spiderlords like Anub'rekhan and his king, Anub'arak held the Scourge itself at bay.
Even with the cunning of the Dreadlords and the onslaught of crushing numbers of undead, the Lich King might not have taken Azjol-Nerub's Inner Kingdom if not for the mistake of the desperate nerubians, who in their attempt to burrow deeper and outlast their undead foes went so far that they exposed themselves to the ancient and terrible forgotten ones. Trapped between these servants of the Old Gods and their undead enemies, the nerubians died in great numbers. Worse, it was found that while the nerubians were immune to the plague, they were not so resistant to the Lich King's directed necromancy, and soon the greatest of their kind found themselves slaves to a new master.
Today, the once-proud nerubians are reduced to undead mockeries serving the Lich King in death, and even when they believe themselves to be free (as Anub'arak did in Azjol-Nerub) they can be raised and forced to serve and fight again and again, trapped forever in servitude. Meanwhile, a small handful of their kind seek to destroy their own former kin who are now crypt lords and crypt fiends and retake their culture from the Scourge.
As to who the surviving nerubians serve, that's an open question.
If they do serve an unseen emperor, we as yet have no idea who he, she (perhaps some ancient nerubian queen?) or it might be. For now, following the events atop the spire of Icecrown Citadel, it has yet to be seen what will befall the nerubians and their quest to free their home.
Next time: the Old Gods themselves.