House Hlaalu  one of the six Great Dunmer Houses, but it lost its status after the Oblivion Crisis, when the Imperials withdrew from Morrowind, and the House was left standing alone as the only supporter of the Empire in Morrowind and thus its status as a Great House was revoked.
As House Hlaalu's territory borders that of Cyrodiil and they are not a warrior house, the Hlaalu quickly embraced the Empire soon after their arrival in Morrowind. House Hlaalu welcomed Imperial Law and the Legions, and the freedom of trade and religion. Consequently, members of the House tend to be well-regarded by members of Imperial factions. They show respect for Dunmer traditions, Dunmer ancestors, the Dunmer Temple, and the Noble Houses, but are more liberal than the other houses.
Because of their connections with the Empire, the House has made many friends and enemies. Ashlanders, and the three vampire clans of Berne, Quarra, and Aundae are all enemies of the house, due to the exile of the Ashlanders by the Hlaalu, and the antagonism of the undead by said Hlaalu. Due to political differences, the House is hostile with the two other Great Houses of Redoran and House Telvanni, but does not maintain open warfare. House Indoril bears much hatred towards the Hlaalu due to the constant assassinations and plots enacted against them after Vivec signed the armistice. The Camonna Tong, a crime syndicate with Hlaalu connections, has managed to put the House on uneasy terms with the Thieves Guild. It is said that much of the Great House is run by the Camonna Tong.
The Great House has bases on Vvardenfell in the cities of Balmora, Vivec, Suran, Gnaar Mok, and Hla Oad. The Duke of Vvardenfell, Vedam Dren, is a powerful ally of House Hlaalu due to his former grandmaster status. The true capital of Great House Hlaalu is Narsis, a city on the mainland of Morrowind, in the south, near the borders of both Cyrodiil and Black Marsh. In Vvardenfell, Balmora is the seat of their power, despite the fact that no councilors live there.
Last days of the Hlaalu
While Vvardenfell was destroyed around 4th-5th year of the fourth era by an enormous eruption of the Red Mountain, the capital of House Hlaalu, Narsis, was on the mainland of Morrowind. However, Argonians invaded the southern part of the province, where Narsis was located, in the 6th year of Fourth Era.
During the Oblivion Crisis, the Empire withdrew most of its armies from Morrowind to defend Cyrodiil from Mehrunes Dagon and his Daedric hordes. However, High Chancellor Ocato said that the Imperial Legion was already fully committed. Whatever the case, House Redoran was able to organize the Dunmer into an effective fighting force against the Daedra, and eventually the Argonians.
Believing that they had been abandoned by the Empire, the Dunmer people's hatred greatly increased. Since they couldn't take their anger out on the Empire itself, they targeted House Hlaalu, who had always been staunch Imperial supporters. The other Great Houses revoked House Hlaalu's Great House status. The House fell into obscurity due to their new-found pariah status until it became a mere shadow of its former power.
However, in 4E 95, a member of House Hlaalu, Vilur Ulen, attempted a coup of the House Redoran settlement of Raven Rock on Solstheim. Vilur managed to influence much of the town into joining his side, but the coup was swiftly detected and brought to an end by the Redoran Guard and Vilur was executed. Many years later, Vilur's descendants infiltrated Raven Rock with the intent of murdering the one who had issued Vilur's execution order, Councilor Lleril Morvayn. Though they hired the services of the infamous Morag Tong assassins, all the conspirators were slain by the Last Dragonborn.
- In a quiz developed by the The Elder Scrolls Online team, House Hlaalu is described as "House Hlaalu members love to negotiate, make deals, and generate a profit, and most members are more than willing to compromise in order to resolve disputes. Still, House Hlaalu’s love of high culture and urban life comes with a (perhaps unfair) reputation that labels them as corrupt, greedy bureaucrats."