Tamriel Rebuilt on Stirk... warning, includes MAJOR spoilers as to Stirk Main Quest!
In the Merethic Era before recorded history, the island of Stirk had a small Aldmeri fort. This fort was abandoned after a short time and more or less forgotten, except for the occasional ship's crew resting in its ruins. Eventually, the Yoku who come to Hammerfell use the island as a burial place for their dead criminals. The fort's ruins are buried by then, but they are uncovered by the Yoku digging a new body pit. Either being effected by Aldmer magick, or being superstitious of this strange underground hall, the Yoku stop burying their dead there. While the reason why is forgotten to time, to this day legends of dead Redguard criminals haunting Stirk remains.
A Dragon Break and some centuries later, the Thrassian Plague strikes and Bendu Olo of Anvil calls the forces of Tamriel to destroy the Sload. One surviving Sload named Y'vaknir hopes to continue his arts in solitude, just like N'gasta would in the distant future on Stros M'kai. Y'vaknir was found not long after his practice began, and he was killed by Olo's army. His lich servant, calling himself Maugrue the Steward and claiming to wait for Y'vaknir's return, finds one of his documents on necromancy and learns the art well enough to summon himself servants who assist him and live with him in the ancient remains of the Ayleid fort.
Time passes. The Remans and the Potentates rise and fall. It is the day of Tiber Septim, the aspiring ruler of all of Tamriel and one of the fiercest generals ever to live. Anvil no longer has a navy like it did in the days of Bendu Olo, though it is still the main dock for the Imperial navy, and Tiber quickly realizes that its capture by his current enemy, the Aldmeri Dominion, would open up the whole of Colovia, the western of the two Cyrodiil states. He could not allow this, and so he had a fort built on Stirk for protection. Ironically, the island that had originally been inhabited by the Altmer and Bosmer's ancestors now was maintained to defend from them. This fort, eventually named Fort Stirk after Armondian Stirk, the military leader placed in charge of the island, is able to send word to Anvil of an attack and also attack such ships from behind.
After the war ends and the Empire is declared, the now aged Armondian sees a chance to earn a fair bit of gold. The island feels the warm Abecean tides and sun, and is a beautiful little paradise. He buys property rights from the Empire and has manors constructed. They are sold to rich families, mainly from Cyrodiil, and it is quickly turned into a resort town. More recently, another entrepreneur found gold north of the city. Not telling Armondian's descendants of his discovery, he buys the land cheap and builds himself a mine with poor working conditions which is the reason for the discontent the island is now facing.
After all of this time, Maugrue the Steward still livse with his undead minions, now deep under the earth with no way to escape, waiting for Y'vaknir's spirit to return to him and claim what he calls Y'vassa for his own and eventually bring the dead - or so Maugrue believes - Sload customs back to life. During the heat of all the current trouble, a wayward mine passage has found itself dangerously close to Y'vassa, and the moaning can be heard in the lower parts of the mines. A miner named Samalt, coincidentally the brother of Marks (the rebel), is very curious about these moanings, and is the only one who will go into the lowest parts of the mine. In town, meanwhile, Cartello Stirk and his guards are worthless to enforce good conditions in the mine or stop the mysterious robberies in the city, and all of Stirk's history is about to burst forth in a gush of insane quest!
this is based heavily on already established lore, but names and stuff were made up.