Spoiler warning: Plot and/or ending details follow.

Marcus is a minor character whom the PC first encounters in his/her first trip to the town of Ember. He makes some cryptic statements at first, referring to the PC as someone who will destroy Ember, but then suddenly states that he is mistaken. Marcus claims that he and the rest of the village will perish, but that he might be spared if the PC gives him an item. He then asks for Bishop's skinning knife, to which Bishop initially refuses. The PC is given the option to force Bishop to give Marcus the knife.

If Bishop gives Marcus the knife, Marcus can later be found down the village well after the massacre of Ember's people. If you speak with him, he will go to the inn at Port Llast and give you back Bishop's knife (which is magically enchanted and becomes an equippable item). During the PC's trial, he is one of the witnesses that can be called. He is definitively revealed to be a seer and he testifies that the real culprit is Lorne, who magically disguised himself as the PC in order to frame him/her.

If the PC dismisses Marcus or does not force Bishop to give up his knife, Marcus cannot be found and is assumed to have been killed along with the other villagers.