The Elder Scrolls V: Skyrim/The Forsworn Conspiracy

The Forsworn Conspiracy is a quest discovered in Markarth. When you witness Weylin attacking Margret at the entrance of Markath, the guards will wait until the scene is over, then try clearing the crowd. Eltrys will approach and give you a note.

This quest has a specific procedure for optimal play, as going too fast may cut you out on the optimal rewards.

This quest can be lost forever if Maraketh is liberated by the Stormcloaks in the civil war quests.

Investigating the murders
Eltrys will wait at the Shrine of Talos. He will explain that the forsworn has killed his father, and that he wants to have it investigated properly.

He gives you to leads - investigating Margret, and Weylin.

Silver-Blood Inn - Margret 's room
Margret stayed at the Silver Blood Inn. If she died, you can obtain the key from her body, or convince the owners of the inn to provide the key. If you managed to save her, you can perform a speech check to obtain information from her.

She provides a lead to Thonar Silver-Blood, although you shouldn't follow this just yet. Instead, visit the shrine of Talos to give new information to Eltrys, along with a partial reward.

When you leave the inn, a guard warns you to stay out of Markarth's business. You can ignore him for now.

The Warrens - Weylin's room
Weylin was a forge worker who stayed at the warrens (near the forge). His room is locked. You can pick the lock, or obtain the key from Garvey.

You can enter his room to retrieve a note, from someone named "N".

When you leave, you'll encounter Dryston who engages you in a brawl. If you win, he will mention that he was sent by Nepos the Nose - otherwise you can pickpocket a note in his inventory, or silently assassinate him.

Before investgating Nepos, head to Eltrys for another reward.

Treasury House - Thonar
Note: Completing this line of investigation will result in the death of Betrid Silver-Blood, as well as prepare an ambush as the Shrine of Talos.

Head to the treasury house. You can use a speech check or bribery to unlock the door to Thonar, or pick the lock instead. Confront Thornar about Margret, and two forsworn spies will attack Betrid. Kill them.

After the battle, Thonar will mention having a deal with the forsworn king in Cidhna Mine, only to discover that they are now out of control.

Nepos the Nose
Note: Completing this line of investigation will prepare an ambush as the Shrine of Talos.

Head to Nepos' house, and ask to meet with him.

When you speak with Nepos, exhaust all dialog options to get as much information as possible. He will mention receiving orders from the forsworn king in Cidhna mine. Once the conversaion finishes, he and the three servants will attack.

Returning to Eltrys
Note: If you need to commit crimes in Markarth, or if you have one of the Thieves' Guild quests, you should complete those first before reaching Eltrys. This can be an ideal chance to augment the Ebony Blade (using the beggar), or otherwise. You should also have at least 40 units of free space for potential inventory use during the mine - if needed, you can use the abandoned house as temporary storage. As you will be stripped of equipment, it's best to ensure you have proper spells before continuing.

When you return to the Shrine of Talos, three guards will ambush you and demand you to surrender. Once the conversation starts, you will have a bounty which cannot be paid off, the only option is to either escape Markarth, or turn yourself in to a guard.

A possible exception is to snipe the guard with a bow before any conversation starts then leave the shrine, or to kill the guards without letting them enter conversation.

No One Escapes Cidhna Mine
In part two of the quest, you're placed in Cidhna mine. If you want to harvest the silver ore veins, you can grab and dual-wield two pickaxes and mine up to 15 units of ore.

Meeting Madanach
Madanach is in a secure section of the mine, and you need to get past the guard. The following options are available:
 * Persuade, pickpocket or brawl Duach or Braig for some Skooma. You can give Borkul the Skooma for the key if you successfully persude him.
 * Trade the skooma to Grisvar the Unlucky in exchange for a shiv. Give this to Borkul for the key.
 * Brawl or Pickpocket Borkul for the key.
 * If you fight the prisoners with a weapon or spell, you can unlock the door, but will have to kill Madanach.

Once you reach Madanch, you can speak with him, before making a decision on how to proceed. However, escaping with Madanach tends to be the more rewarding option through magic items alone.

Escaping with Madanach
If you want to release Madanach, speak with him. He will ask you to do a few things. Once you complete those two, Madanach will gather the prisoners, and lead them through an escape tunnel. Follow them to the exit - they should easily defeat the spiders and other enemies in the tunnel.
 * Speak with Braig, and listen to his story.
 * Kill Grisvar the Unlucky.

At the end, you will have your stuff returned, in addition to receiving a full set of enchanted armor. Overall, the armor pieces provide 15% reduction in destruction spell cost, a 20% bonus to sneaking, +20% damage with bows, and increasing magicka by 30 points. Additionally, your bounty will be wiped clean.

Killing Madanach
If you prefer to kill madanach, you can simply kill him when you see him. This will turn most of the other prisoners hostile, thus you will need to head to the exit. At low levels, fighting the spiders and artifacts tends to be more difficult, especially if you haven't specialized in spells.

When you finally escape, you will be told by Thonar Silver-Blood that he has arranged a pardon, and rewards you with the family ring, which improves smithing by 15%.

Both rewards
If you want both rewards, kill Madanach after he gives you the armor of the old gods. This may be a difficult fight, as you engage against the other prisoners at their full strength.

Later escapes
If you want to escape from Cidhna Mine in the future, return to the cell and place both keys on Grisvar the Unlucky, or use other means to smuggle items into prisons.