On this page of the Assassin's Creed Valhalla game guide, you will find a detailed walkthrough description of the mission Impaling the Seax.
Two members of the Ancient Order were eliminated. It is time to make sure that the Seax is truly dead.
Reward: 3400 XP.
Report to Goodwin
Go to the inn in Wincestre to talk to Goodwin. If you ask him if he thinks The Seax is really dead, he won't be convinced of it. The bishop undoubtedly died, but it is not known if it's him who was hiding under this pseudonym.
Attend the Bishop's funeral
Go to the cemetery at St. Peter's Church to take part in the funeral to see if the bishop is really getting buried and if he belonged to the Ancient Order.
Talk to Harriet, the bishop's sister, first. If you have level 4 charisma, you can continue the dialogue. If not, you will find the necessary information another way.
Examine the body wrapped in white cloth. The face of the deceased was burned, but there are no other signs of burns on the body. What is more, the man's frail body does not fit the description of the portly bishop's figure.
Go up to the tombstone to find ordinary peasant clothes there. A strange find for a church cemetery.
Talk to Wemba, who takes care of the cemetery. When you ask if he buried Ealhferth, he will ask if you have seen his missing friend Leof. Continuing the conversation, you will learn that it was he who was stripped of his face and wrapped in a white cloth to fake the Bishop's death.
Go back to the Bishop's sister and talk to her again to inform her that you have discovered the truth about her brother.
After the truth comes to light, Harriet will run to the crypt, and guards will enter the cemetery. After the fight, talk to the woman again to find out that her brother is planning a great comeback and will take the place of King Aelfred.
Find and assassinate the Seax
Go to Witan Hall, then climb up the wooden scaffolding and enter the building through an open window.
A member of the Order hides in the crowd as one of the guards and waits for the right opportunity to attack King Aelfred. As soon as Ealhferth yells and reveals his identity, attack from above and immediately finish him off with the Hidden Blade. If you do not manage to kill your opponent with a single blow, you will have to fight him.
Find the Order's temple
Go to the bishop's residence, then walk through the small door by the city walls, where you'll open the door at the very bottom of the tunnel to enter a ruined temple. Search the area for clues.
The first one is a letter, which you will find on a wooden box. The content of this letter may be of interest to Hytham.
The second clue can be found in a closed room. Walk down the corridor on the left side, then move the heavy rack to the side to discover a passageway that has been buried in the rubble.
You will find an oil jug in the corridor on the right - just slip through a narrow gap in the wall. Break the rocks and enter the room.
Inside you will find another document from which you will learn that the Order did everything it could to weaken the king's position, and the lead given by Harriet was wrong. It is time to go to Aelfred and talk to him.
The king, accompanied by many guards, will give Eivor his ultimatum to live among them as a Christian or die as a heathen. When Eivor refuses to submit to the king's will, he is considered a threat and must flee the city. As soon as the guards discover your presence, they will attack immediately, but you don't have to fight them if you don't want to.
When you get to a safe place or when the guards stop chasing you the mission will be over. As a reward you will receive 3 400 XP.