The Ritual of the Berserker is a quest under Ravensthorpe in Assassin’s Creed Valhalla.
Your task is to first concoct the Berserker Brew and face the enemy.
Here’s a walkthrough of The Ritual of the Berserker in AC Valhalla.
Suggested power: 20
To begin the quest, get to Edmund’s Hope which is in East Anglia. The exact location is shown in the map below, marked by the quest symbol.
Get the nightshade
You will see the nightshade in the cemetery beside the church.
Head to the Gallows Tree
After obtaining the nightshade, go to the Gallows Tree which is just southwest of the area.
The tree is unique so you won’t miss it. You will meet Bjorn here.
Defeat the bear
After drinking the concoction, you have to defeat the bear in a hallucination.
Finally, talk to Bjorn to complete the quest.