Continuity mistake: After Nardole gets Pictish facepaint, the lines change in consistency and exact positioning several times throughout the episode.
Continuity mistake: When the Doctor and Nardole are being held by the Picts in a circle of weapons being pointed at them, when Kar's brother points a knife at the Doctor and warns him not to speak until she gets back, his arm is almost fully extended in shots from above and facing the Doctor, but much more bent in shots facing him. (00:12:40)
Chosen answer: No, no information is avalible for the identity of the entity.
Repo_Man