Towards the end of Assassin's Creed Valhalla's Grantebridgescire arc, players will be tasked with figuring out which of Soma's inner circle advisors betrayed her. It's a difficult task as all of the suspects are relatively likeable and each of them have some evidence that could be considered incriminating. Without the full story, players will have a hard time knowing for certain.
Assassin's Creed Valhalla has the player make choices for Eivor frequently, but it can be difficult to tell which ones actually matter. In this case, the choice is somewhat important, as choosing correctly will allow players to recruit a new ally for their raiding party. Thankfully, the traitor is always the same, so players that aren't into sleuthing can read the answer here.
There is a way for players to figure out who the traitor is on their own. It involves paying attention to Assassin's Creed Valhalla's small details, searching the town thoroughly for clues, investigating the tunnel to find a trail of yellow paint, and then following a stream of ship wreckage in order to identify which ship was painted yellow. The owner of this ship is the culprit, but players should stop reading if they want to figure it out for themselves.
Ultimately, Galinn is the traitor that told the enemy forces about the secret tunnel. In order to ensure his own safety, he stole the yellow paint and hastily covered his longship in it to indicate to Saxons that he was their informant. Players should inform Soma of this immediately and a cutscene will trigger in which she slits his throat. Though she's sad, she's ultimately grateful for the player's help and the questline continues. By the end of it, players will have the chance to recruit Birna to Eivor's ever expanding raiding party.
If players choose incorrectly, Soma will kill an innocent and Galinn will remain quiet. At the end of the questline, he reveals his betrayal and turns on the player and Soma. The remaining surviving advisor is wounded and almost killed, and ultimately players have the choice to either send Galinn to Valhalla or deny him that right. This ending does allow for a boss fight, but makes Eivor seem foolish and causes more death and suffering than is needed.
Choosing Galinn as the traitor is easily the cleaner option, but players that want an extra boss battle and thirst for challenge may actually want to pick someone else instead. The biggest drawback of this is that Birna will not join the crew even if she survives the endeavor, and from a moral standpoint Galinn causes a lot of carnage if he's left alive.
Assassin's Creed Valhalla is available now on PC, PS4, PS5, Stadia, Xbox One, and Xbox Series X.