Horns of Veithurgard

Horn #1: After docking on the larger island to the south, defeat the enemies. Head along the dock to the left of the beach. Defeat the Projectile Draugr and find the Horn at the far end.

Horn #2: On the main beach, head right from the boat to find a chain. Pull it and use your axe to freeze the runic gear in the upper right corner. Follow the wall forward to the now open gate and a wall to scale. Climb it and follow the path down at the top to a boarded wall. Break it open and search the corpse at the end to find this Horn.

Horn #3: Once you reach the anchor that binds the Dragon, head to the open area on the left. You'll spot a waterfall on your right; at the bottom of it sits a corpse with this Horn.

Horn #4: When you reach the entrance to the castle, turn around to see a bomb blocking the bridge. Destroy the bomb and jump the gap to find the Horn by the corpse on the other side.

Horn #5: Enter the castle and kill the two Reavers that ambush you to the right. Proceed to the end of the room where another two Reavers ambush you. Once they are dead, check the corpse for this Horn.

Horn #6: Head further into the castle and lower the water level by activating a switch. Drop down the ledge to reach the lower room, defeat the Tatzelwurms, and find the final Horn on a corpse.