Badge of Vows 86 is a quest item from the From A Different Sky - Part 9 DLC. Merely picking it up satisfies the goal needed to complete the quest.
Badge of Vows #86 is located in Gran Soren on the roof of Arsmith's Alehouse. The west tower near the south gate can be used to climb to the elevation of the neighboring roof. A series of jumps across the rooftops will be enough to get you on top of the Alehouse.
The starting point (S) is between the two towers at the southern entrance of Gran Soren. Go inside the northwestern tower and climb the stairs to the second floor. Climb the ladder on the second floor to reach the third floor. Head north through the archway to reach the ramparts outside. Follow the pathway northwest, then northeast to the first rooftop. Jump down on this rooftop and head southeast until you reach the gap in the street between the two buildings. Jump due south towards the lower rooftop. Head east across this rooftop, ascending as necessary until you reach the badge.]