When the fight starts, ignore the wyvern and head to the rear of the courtyard.

This boss fight is very different to the others - from the right spot, he can be defeated with a single blow, but getting there and timing it can be tricky. Now head back down and pull the lever to open the portcullis, and make your way into the courtyard to trigger the boss fight. Follow the stairs up and defeat the enemies above the arch - the second one is a little larger than normal and packs a fire breathing attack. Walk up the broad stone steps and take the narrow path on the left when you reach the arch. Dodge the fireballs as you make your way along the path and tackle three more snake-lizards then light the bonfire just ahead. As you round the first corner you'll be confronted by a couple of snake-lizards armed with scimitars, and around the next corner you'll come under fire from up ahead. Take the exit on your left, head up the stairs, and then use the gesture on the empty rug to the left of the baby dragon and wait 5 seconds or so to be transported to a new area. Head to the sewer entrance, turn right into the collapsed tunnel, and make your way to the large room filled with the branding iron enemies.