Path of the Deathless - Enemy of My Enemy
Light 6 signal braziers.
After clearing out the first courtyard of Deathless, climb onto the middle structure. Aim for the northeastern corner to see the first brazier.
Turn to the right to face the southeastern corner, where you'll see another.
When you head up the next staircase, Deathless will fire at you form a vantage point. Take them out, go to their spot, and face east to see the third brazier across the way.
Start up the next set of steps and turn around to face above the vantage point where you were just standing. Pull down the rope arrow door up there to reveal another brazier.
When you leave the fortress area, turn around to see an alcove covered by wooden planks. Shoot through these to reveal the fifth brazier.
Check the other alcove along the same wall for the final brazier.