This quest begins immediately after Walls and Shadows. Now that you’ve identified The Leech as a potential suspect, it’s time to work with Erke to track him down.
Meet with Erke
You’ll find Erke by the docks just south of the Temple of Sulis Minerva. Speak with him to begin the quest. You’ll have a few dialogue options during the conversation, but it doesn’t matter which you choose. A woman named Gyda will provide you with a lead.
Follow the Contact
When you near the bridge, use Odin’s Sight to identify the precise location of the crate that you need to hide behind. Get behind it and interact with it to begin a cutscene in which the contact appears. After the scene, you’ll need to follow him through the streets of Lunden. As you follow be sure to keep a reasonable distance from him; if you get too close, he’ll turn around and spot you. He’ll also stop occasionally regardless, so you’ll need to be ready to hide when he does.
The contact will eventually reach Bodilsburg Garrison, on the far eastern boundary of the city of Lunden. Keep your cloak on here as you enter, and don’t worry if you lose sight of the contact. The main thing to be concerned about it not being seen by the guards, so take your time to infiltrate the garrison carefully. You should begin by climbing the walls to reach the rooftops, where you’ll have a good vantage point of the building where you’ll find the contact.
Infiltrate the Building
Once you’re on the roof, use Odin’s Sight to highlight the building which the contact entered. You’ll find it just southeast of the entrance to the garrison. At this point you can choose to sneak your way in, or you can kill all of the guards in the surrounding area if you’re spotted. The contact will remain unmoved in the building regardless of your choice. If you prefer a stealth approach, follow the rooftops of the buildings to the southeast and make use of the tall grass when you approach the contact.
When you near the building you should note a haystack beside it. Enter this and attract the attention of the guard in front of the building with a whistle. When they approach, you can assassinate them and then quickly enter the building. You may need to wait for patrols to pass by before you leave the haystack. Alternatively, you can shoot the guard from the rooftops before you jump down.
Whichever way you do it, once inside the building you’ll encounter a man named Oija, who you’ll need to deal with by threatening him, attempting to charm him (requires Charisma level 2), or by convincing him that you’re a member of the Order of Ancients. The first two options will inevitably lead to conflict, and as the blacksmith of Sister Frideswid, you may decide that he deserves death regardless, but if you want to find The Leech without having to kill Oija, you’ll have to tell him you’re a member of the Order of Ancients. What happens next depends on whether you have an Order Medallion in your inventory. For a full breakdown of your choices, see How to Convince Oija. If you do fight Oija, he’ll be marked as a regular War-Band Chief, and will fight like one, too.
Once Oija is dead the entire garrison will be alerted to your presence. You can fight them all for XP and loot, or you can simply flee the garrison to the next stage of the quest.
Find and Kill The Leech
When you kill Oija he will drop a note for a Tool Order. This will reveal the location of The Leech at the nearby forum, northwest of the Bodilsburg Garrison. You can enter the forum courtyard from all sides, but you’ll find The Leech in a building at its northern end. Use the narrow corridors surrounding the forum to make your way inside the building, assassinating the guards as you go. When you enter the building you’ll find The Leech, now revealed to be Sister Frideswid, a member of the Order of Ancients, alongside a Woe-Bringer. You can try to assassinate Frideswid before being seen, but this can be difficult in such close quarters. If you’re spotted, Frideswid will run into the courtyard to get away from you. Hunt her down and kill her by any means necessary.
As you meet Frideswid in the courtyard she should turn to face you. You’ll now need to fight her and a bunch of enemies including the Woe-Bringer, a War-Band Chief, and a Blood-Vikingr. You will also need to take out some archers on the rooftops surrounding the courtyard. When all the enemies are dead, you’ll need to confirm the kill of Frideswid to initiate a cutscene, as with all the deaths for Order of Ancients members.
After the cutscene, return to Erke at the docks behind the Governor’s Villa to complete the quest. You’ll have to choose whether to burn Frideswid’s book or keep it, but it doesn’t matter which you choose. We chose to keep it for the sake of posterity, but it doesn’t have any real implication to the story.