So I was playing around in Telvannis today, and noticed an Imperial Fort that might well serve for the next leg of an Imperial Legion questline in the Quest Pack. Though the ending gets a little weird, this questline practically wrote itself:
Quest 1: A Crumbling Fort) After the events in the Watch of Fire questline (or even before, if the player happens to stumble upon it), the player is sent to Arvs Rathrethi, the captain of Fort Windmoth, for their next assignment.
Fort Windmoth is a run-down sorry excuse for a fort, and this is clear upon first entering it. (Someone has even already set up one of the guards selling skooma and moon sugar--what a coincidence!) The player is first set to do manual labor down in the prison area. The prison has recently collapsed on one of the prisoners (already implemented) and the Legion wants the player to shore up the prison area with some beams.
The player is let into one of the cells (the one with the skeleton in it) and told to get to work. While they are working however, the guard "accidentally" closes the door and locks it. The guard claims the key broke off in the lock, apologizes, and says they'll go find the blacksmith to fix the lock. The way they say this to the player should make it pretty obvious that the lock is not actually broken, but that this is another attempt on getting rid of the player--the guard hopes another cave-in will kill them before the lock can be "fixed".
At this point, the player's only option is wait it out. While they are asleep, a cave-in does indeed occur, blocking off the cell door but opening up a little passageway behind the cell. In this passageway the player finds an eccentric Telvanni wizard, sporting a chameleon spell. The Telvanni says they are studying subterraenean mushrooms and their attention was drawn to the peculiar geology around Fort Windmoth. He babbles on a bit about alien Imperial architecture and mushroom roots before the player wheedles out of him that Fort Windmoth collapsing is not because of shoddy craftsmanship, but because it is built on top of a Dunmer burial ground.
The Telvanni can be convinced to teleport the player back up topside so long as the player agrees to help him find some mushrooms. This is handled in Quest 2.
Quest 2: Mushroom Madness) The player agrees to help the Telvanni find some mushrooms and is teleported back into the courtyard. The player is essentially affected by a geas spell, in which they must get the mushrooms or suffer a painful death. Unfortunately, some of the mushrooms are only native to other parts of Tamriel, out of reach to the player for all practical purposes. The player is now faced with a dilemma of how to not die before they can get these. A few options are available:
1) transfer the geas to one of the others in the fort (can be done through persuasion, trickery, or force, depending on the NPC--and on how evil the player wants to be)
2) talk to the traveling trader in the courtyard to obtain the mushrooms (week-ish wait time, some stat and health penalties from the geas)
3) bribe and/or threaten Naleth into making use of his black market connections to get the mushrooms to Windmoth sooner (higher cost, but less wait time and so no penalties)
4) track down the Telvanni wizard in one of the towers and slay him (hard battle)
After using one of the above methods of satisfying the geas, the player finishes the quest. There is no reward for this one (unless the player killed the Telvanni; then they get what's on the corpse).
Quest 3: Blood is Thicker than Water) There is another cave-in in Fort Windmoth, and one of the walls has collapsed. Arvs Rethrathi is getting increasingly desparate to find a solution. He says that the Fort WIndmoth garrison is unusual in that it has enlisted many Dunmer. One of them, Sarethi (I forget the last name--he's already ingame) reports he was dutifully communing with his ancestors as all good Dunmer do, when they began expressing extreme displeasure with something to do with the Fort. Since Sarethi is not a priest nor a follower of the Tribunal/Daedra, he cannot decipher his ancestor's message. The player is asked to go to a Temple and ask for one of the priests to get out of his ancestors what's up.
The priest tells the player they can't commune with just any ancestors without the proper ritual. Luckily, Sarethi thought of this and gave the player some Ash Salts and a heirloom of his family--an amulet in the shape of a birch leaf. The priest recognizes the family from this heirloom, and refuses to help the player, saying the family has long been adrift from the Tribunal's teachings, worshipping Aedra, maintaining close relationships with outlanders, and other such distasteful habits.
So the player must return to Fort Windmoth and report their failure. Again, no reward.
Quest 4: But Not as Thick as Thieves) The player returns to find Sarethi talking with an Ashlander farseer. He says she appeared out of nowhere and asked to speak to him. The farseer tells a peculiar story, of how she received a dream sending of a dragon eating a mountain (symbolism of the outlander Nerevarine killing Dagoth Ur), of a fiery eye opening and crying tears that became Daedra, before it is stabbed by a hand bearing a prison cuff (symbolism of the Hero of Kvatch). Finally, she tells of the dragon returning to lay the countryside to waste with its fiery breath, until it came to a fortress she identified as Fort Windmoth and there was blown away by fearsome winds (symbolism of the Red Year, the collapse of the Empire, and Dunmer of the future taking refuge in Windmoth to escape these calamities). She goes on to say that an ancestor of hers and an ancestor of Sarethi's were once tight friends in the past. She says they must work together again to ensure their descendants' safety in the future, by stopping WIndmoth from falling (literally!)
To do this, she asks the player to escort her back to the prison area and have the Legion carve out some new tunnels on her bidding. The Legion is very doubtful of this farseer however, and have to be convinced. The workers are currently under the thumb of Naleth Llarni, the skooma dealer. In a direct flouting of the Watch-of-Fire plotline, the player must arrange that Naleth's black market trading can continue before the workers will agree to help out.
Quest 5: Price of Blood) The Legion gets to work on digging, and the player has to return in a week(ish) before their work is completed. The new tunnels reveal an ancient Dunmer burial site under the fort. In the main chamber are several hollow pillars of stone, arranged reminiscent of a pipe organ, which the spirits of the ancestors give voice through. It has been the "shouting" of these ancestors that has created Windmoth's structural instability, and they must be calmed before the Fort can become stable again.
The ancestors are clearly angry because the descendants of Imperial Legion soldiers like Sarethi have betrayed their roots and taken to outlander ways and (in Sarethi's case at least) worshipping outlander gods. The player can calm them in a few ways:
1) Persuade the ancestors that while the Dunmer have forgotten their culture, they haven't forgotten their kin, and keeping Windmoth intact will ensure the safety of their future family, based on the farseer's visions.
2) Command the ancestors to manifest and challenge them to combat.
3) In the ancient bloody ways of the Daedra, sacrifice soldiers of the Legion to satisfy the ancestors' demands for blood. (In this way, the player can get their revenge on Naleth, but would have to kill Sarethi too...)
Once the ancestors are satisfied, the player can return to Arvs for their reward. Arvs is thoughtful at this development, saying that perhaps for Dunmer, ties of kin are stronger yet than ties of god or country. He says they must of course prepare for the calamity that the farseer foresaw and keep Windmoth open as a place of refuge for future citizens of Morrowind. Implied is that Windmoth will also be a haven for the black market skooma trade as well...