There are cursed symbols scattered throughout the game world of Assassin's Creed: Valhalla that must be destroyed. If the place is cursed, you will definitely find a mark nearby that can be destroyed. Damned places affect their surroundings: it becomes so gloomy that it loses its cheerful and vibrant colors. In addition, Eyvor himself feels so lethargic that he can hardly move; also nearby you can often find the corpses of warriors.
To destroy the cursed symbol, you will need a bow and enough arrows, since they can only be attacked from a distance. For destroying ten symbols, you will receive the Dreamcatcher achievement.