The Iron Flail

 is a main quest in.

It is automatically started after speaking to Deryan in Stalwart Village during The Forgotten Army.

Synopsis
The objective is to gain entry to the Iron Flail Fort in order to discover the fate of the Stalwart delegation sent to negotiate peace with the Iron Flail commander, Adaryc, and resolve the situation.

Walkthrough
"As the last maegfolc falls, a tide of essence sweeps through the ether. It washes over you, and you find yourself in the memories of the Eyeless.
 * Talk to Deryan in Stalwart Village.
 * Go to Iron Flail Fort on the world map, and gain entry to the fort. There are three ways of getting inside:
 * Blast down the main gate, by way of a cannon barrage (requires Ready the Cannons to be completed).
 * Assault the main gate, using a battering ram (interact with the logs beside the draw bridge).
 * Stealthy approach. This is best attempted at night when the guards stay at their campfires rather than move within the camp all the time. Climb over the Western side gate using Rope and Grappling Hook, or squeeze in with an Orlan main character or by casting Form of the Helpless Beast on your party if you have a caster. You need to lead with a character (or an Orlan main character) with 6 Stealth to avoid waking up the sleeping guard.
 * Find and talk to Adaryc, inside the Command Post. Sneaking through the camp is a challenge, but can be done if you do it at night and avoid dogs like the plague. Use a Stealthy character to clear the way first. Moving along the northern edge of the fort can be a good idea, especially if you use the battlements and the stairwell to your advantage. If you are confident of your fighting/stealthing skills and your MC is stealthy, you can leave your party at a tavern and proceed alone
 * You meet the commander in an automatic cutscene, where he also reaches out to you with his Watcher talents. The experience is particularly painful and Adaryc will be shocked to realize that you're the Watcher at Caed Nua (he isn't up to date on the news).
 * You can attack and wipe him out... Or resolve the situation peacefully. (Whether or not this works seems to be dependent on how many of his underlings you killed on the approach.  Being stealthy is recommended if you wish to resolve the situation without further bloodshed.  It isn't necessary to completely avoid killing his soldiers, but kill as few as possible.) It is possible to have a peaceful resolution even if you wipe out all hostile guards in the fort including those outside on the perimeter. He will be extremely hostile at first, but with the right dialogue options, including asking if he has a cure for being Awakened, telling him you saw a vision of an army too, using Intellect options, telling him to read your soul, and finally saying perhaps two Watchers can solve the problem. He will eventually surrender peacefully. This option may require a high Benevolent and Honest reputation (he will say you are soft hearted when he reads your soul).
 * To calm him down. The chat where you ask him about Readceras or use Perception 11 or Intellect 14 to inquire about the shameful treatment of Watchers there are sidelines. As long as you don't explicitly attack him, you can keep exploring the dialogue tree. To progress towards a peaceful solution, ask him about the delegates and his mission. He wants to control the cannons of the Battery to turn them against the Dyrwood once it invades Readceras, as he saw in his vision. You can then tell him that you had the same vision and when he doubts you, you can use Intellect 14 to point out that Dyrwood couldn't possibly wreak the kind of destruction he saw, Resolve 16 to point out that dying  won't do Readceras any favors, rationally point out that you made a mistake in assuming the Iron Flail to be the army from the vision, or mention the thunder and a hundred eyes.
 * Then, you can use a Negative 2 reputation with Stalwart, tell him to read your soul, or point that if he's wrong, he's wasting men and material on confronting the enemy. Then you can suggest that two Watchers can succeed where one could not. He gives you his Soulbound blade if you convince him to stand down and he and his army will march to your aid during The Battle of Yenwood Field. You are also granted the skill Sever the Soul after completing this encounter.
 * Free the Stalwart delegation from their cell by interacting with the grate and talk to them. Saving them will gain moderate positive reputation with Stalwart, but making peace with Adaryc will gain minor negative reputation. The raving delegate, the one who was screaming about drowning and waves, will shortly open her own jugular.
 * Interact with the Soul to have a Vision. It turns out that the delegate was a deep cover operative from The Abbey of the Fallen Moon, ordered by High Abbot Kaoto to drive the Readcerans from the mountains, then report to him or the Tidebringer after the mission is accomplished... So that they can call off the army of the Eyeless. As you learn the truth, there will be a sudden, deafening crash outside, heralding trouble for you, together with the sound of smashing timbers and panicked screaming.
 * Exit the Command Post to meet and fight two Eyeless Hammers.
 * This will trigger another vision, where you find yourself in the memories of the Eyeless:

The hulking creatures surround you, their sinew-wrapped skeletons clanking and screeching in the semidarkness. Their bodies fill the air with the tang of metal and the musk of sweat. The cavern in which you stand - it looks like a cavern, anyway - glows with a dim, ambient light. Steel flashes as the Eyeless shift and stir. They stamp their feet and groan in rasping, metallic voices. Their restless energy prickles at the back of your neck.

You begin to wonder how many Eyeless are crowded around you. You suspect there must be scores of them - maybe more. It's difficult to tell how far back this chamber goes. Or where it is. Ahead, you see a glint of light. It might be an exit. Already, however, the vision is starting to fade.

[Explore further into the chamber.]

You push past the lumbering Eyeless and cling to the wilting shreds of the vision. The cavern broadens before you. It swells with echoes until you hear the growling, grinding sounds of the Eyeless all around. You pull yourself onto a glowing, crystalline outcropping and survey the expanse of blunt heads and piston arms. There aren't scores of them. There are hundreds.

[Investigate the glint of light.]

You push past the lumbering Eyeless and cling to the wilting shreds of the vision. The light up ahead is blinding after the dark of the cave. You rush toward it even as it fades into a pale blur. You can't see where you are, but you hear a cold wind whistling through the gap and feel a spray of moisture sting your cheeks."


 * You automatically gain The Rising Tide quest after the vision. Adaryc will offer a parting word if you managed to talk him down.
 * Go back to Stalwart Village and speak with Deryan - you can gain minor reputation with Stalwart Village