Lieutenant York is a member of the Kinshra who guards the ground floor[UK]1st floor[US] of the Black Knights' Fortress. He will challenge as to why Sir Owen is unbound during The Death of Chivalry. Implying that he thinks you are weak will force him to back off.
He appears again during Curse of the Black Stone. Similar to the last event, he will challenge as to why a low ranked Kinshra knight is leaving the Fortress. After hearing the player's reason, he asks the knight why they are going. He will then stand aside after Tessa's soulbound armour intimidates him.