Coloured markers are used to track various things on the board and cards, such as the Morale level, Weapon level, how many times Starting Equipment has been used, and so on. They are also used to cover up things that are no longer available, such as exhausted sources on Island tiles.
Coloured markers are also used in different scenarios to represent different game elements, or to cover up icons. The scenario descriptions explain how to use these markers.
Wooden markers are also used to represent resources: food, wood and fur.
Markers are wooden, and distinct from tokens, which are cardboard.
If you are supposed to place a marker (other than a resource marker), but you can’t because there is already a marker with the same meaning there, this counts as unfulfilled demand and characters suffer 1 Wound. This can happen if, for instance, a source is already exhausted and you are then instructed to place another black marker on it.