This quest begins immediately after The Welcoming Party. After establishing a plan with Ljufvina, Eivor has decided to search Jorvik’s Archives to find answers on why the Christian texts are being stolen.
Investigate the Archives
You’ll find the Archives just west of the Royal Hall. Once inside, you can interact with a number of items to learn more. The main item you’ll need to inspect to proceed with the quest can be found on a table in the southeastern side of the Archives. when you do, a brief cutscene will begin with Audun and Ingeborg, during which you’ll have a few dialogue options. Choose as you want here. After the scene, you’ll need to visit the Rectory and explore it. You’ll find this over the bridge to the northeast of the Archives.
Explore the Rectory
To reach the Rectory quickly from the Royal Hall, go to the northern end of the hall and use the zip line to cross the river. When you arrive at the Rectory entrance, Eivor will speak at the steps and you’ll have to investigate the two teal objectives in the buildings to your left and right (use Odin’s Sight to highlight the objectives).
To enter the building on the left, go to the back of it and move the barricade away from the window. You can then shoot the lock on the front door, allowing you to enter. When you do you’ll encounter a priest in distress. Speak with him for more information, then enter the building on the right (southeast of this one). You’ll need to enter this one from the roof by shooting through the wooden barricade there and dropping down. Once inside, speak with the priest.
After the conversation with the priest you’ll need to follow him to the bishop’s quarters. When you arrive, move the barricade back from the entrance and explore the quarters by examining the items within. These include burnt Christian texts, blood near a cross, and the bishop himself. You’ll need to move the bishop off the chair to inspect the note beneath him. When you do, a cutscene will follow, after which you’ll need to leave the quarters to escape the Red Hand guards.
Infiltrate the Minster and Where to find Firebrand
You can sneak out of the quarters the same way you came in, or you can kill the guards instead. Either way, the next move is to infiltrate the Minster, just northeast of the Rectory. To get inside the Minster, climb to the top where the wooden scaffolding is. You’ll find an open circular window here which you can climb through. Once inside, use Odin’s Sight to highlight a teal objective, and make your way to it. As you approach a cutscene will begin, during which the Abbes, Ingeborg, is revealed to be the Firebrand.
After the cutscene you’ll need to find and assassinate Ingeborg. She could be in any one of three places in and around the Minster. The first is in the main room of the Minster where the cutscene took place. The other two are west and south of the Minster, as shown in the screenshot below. Explore each of these and kill the guards as you go. Among the guards you’ll find various impersonators of the Firebrand. These will be easy to kill, and their only noteworthy ability is to heal themselves back to full health when they’re low.
Ingeborg herself can take the form of a regular or elite guard such as a War-Band Chief or Marksman. As such, you should be able to kill her just as easy as any other regular guard. When you find and kill her, confirm the kill and then speak to Ljufvina at the Royal Hall to complete the quest.