Dun Mora used to be one of the great border fortresses of the High Elves, until it's fell to hopelessness and self-pity, and cursed the Light-Gods. Then the Godess Elen punished them and sunk the fortress into the swamp.
Today it is the place where the Morhir, the Elven outcasts do their services and go through the Trial of Sorrow. They defend the ruins of Dun Mora against the demons of Evermarch in the hope of being reaccepted into the groves of Finon Mir again.
The Morhir, the elves of Dun Mora seem to be afflicted by a strange kind of apathy, they ar enot addressable and they do not defend agaisnt the attacks of the swamp demons. In this condition they can not help you in your upcoming battle against the Bullwark, you have to find a way to free them from the paralyzing sadness that has taken a hold of them.
The Queen of the Morhir has gathered those elves around her that have not fallen to the hoplessness. Follow your sister Shae to the Queen and ask her help for your cause.
The Mourning Ghosts
The mourning ghosts of fallen Morhir deprive the Morhir of their power and mkae them apathic and defenseless against the demons. If you manage to redeem the ghosts the elves will regain their strength and be able to help you in your cause. You can not simply slay these ghosts, each of them is tied to the world in their own way and requires an individual approach to find rest.
There are 5 ghosts, two can be persuaded to leave their living sisters alone, one has to be fought. For two you need something from the swamps and it could be helpfull to explore the area south of the elven city before your first conversation with the Queen.
From the Depths
Somewhere int the North of the swamps the demons have found a way up to the light. In the hour of the ghost, when you can hear the whispering of the dead, they sneak around and attack the elves of Dun Mora. As long as the elves have to fight them they cannot help you against the Bullwark.
Time is running
In the hour of the ghost, when the dead whisper to the living the demons will return. You only have until then to redeem as many mourning ghosts and free as many of the Morhir as you can in the time you have.
The First Battle
The demons have returned the feast on the living elves, but this time they will not find apathic victims. Defeat the demons with the troops you managed to release. You can free over 30 archers and druids, send them all to the journey stone in the elf city. Split the army in two (or three parts) after the fight.
Back to the Queen
One attack has been repelled, but it is not over yet. Talk with the queen of the Morhir about further actions.
They're coming back
For now the demons have been repelled, but now they know you're here they will likely strike back in retaliation. Prepare for war, when the Whispering can be heard again, they will strike with far greater numbers then what you've seen thus far.
You'll gain command over the base south of the city and 18 minutes to prepare. Use the elves (split them in two groups) and your party to defend the base from small groups of elementals coming from the west, south and (south-)east. Build additional workers, a stonemason, smeltery and alchemist, further east and west are more resources, use them. Build farms, a tower here and there and an army and have them ready at the journey stone in the center of the elven city when the 18 minutes are over. Then crush the demon army.
Back underneath the Ground
Dun Mora escaped, again, but as long as the demons can freely travel here from their realm, the elves remain tied up. The portals that grant the demons access must be destroyed. Gather the army you've mustered plus the freed Morhir and go north to destroy the demon camps and their portals.
The archers of the Morhir
With the liberation of Dun Mora you should have won the bows of the Morhir for your casue. Now the attack on the Bullwark can begin.
The elven Oath
The Elves of Dun Mora are free, hopefully they will now help you with their bows. Talk to Io for their support.
The battle begins
The elves also support your cause, hopefully King Ulf of the Highmark will now support you. Return to Sevenkeeps.