In Assassin’s Creed Valhalla, you need to form alliances with territories nearby to expand your settlement. When you set out to form an alliance in Grantebridge, you will meet Soma. In the Grantebridge arc, your objective is to help Soma defeat Wigmund and regain control over Grantebridge.
Before the fight against Wigmund, Soma learns that one of Soma’s three most trusted advisors, Birna, Lif, and Galinn, is a traitor. She asks you to gather evidence around you and find the traitor. This is quite a tricky mission since it can significantly impact the game’s story and Eivor.
To find the real traitor, you need to gather evidence in and around Grantebridge. You can speak to the people in Grantebridge, and you will find that both Lif and Galinn have alibis. Birna was with other people in Grantebridge at the night of the attack while Lif was at his shipyard. On the other hand, there is nothing known about the whereabouts of Galinn.
If you proceed from the tunnel in Soma’s longhouse, you will find some yellow paint along the way, which will lead you to a bucket of yellow paint. Upon further investigation and speaking with Lif, you will get to know that Lif had his paint stolen, which was used to paint the ship used by the invaders. This further proves his innocence.
After gathering all this evidence, you can finally go and tell Soma that Galinn is the traitor. Keep in mind that if you choose the wrong traitor, that can significantly impact the game’s story. Apart from the fact that choosing the wrong person will result in him getting killed, it would also mean Birna will not be joining your crew.
On top of that, it can affect your relationship with Soma and make her colder towards you. If you want to see how the story pans out, if you choose the wrong traitors, you can do so by creating a save just before talking to Soma since replaying the mission isn’t possible.