"Light third bonfire with fire damage" is an objective in the side quest Lost Souls in Tiny Tina's Assault on Dragon Keep DLC
Walkthrough[edit]
Head to the South from the second bonfire then turn to the East. This will lead you to the final Bonfire that you need to light. Approach and fire on it with a Fire-Type weapon to ignite it and trigger the conflict. You will encounter Fractured Skeletons and likely encounter even more kinds of Skeletons as you work to hunt down the targets.
