How am I supposed to put out fires?

Okay, so I finally made it to the Crucifixion Swamp and I found a writing that said if I put out three fires then I'll be able to reach Wolf Blood. How am I supposed to do that? I tried using slugs, I tried interacting, I tried breaking them. What am I supposed to do?

You are probably trying to put out the wrong fires. Quest fires are interactable objects looking like bowls with flames. When you are close, the prompt "Extinguish flame" is shown:

There are exactly 3 fires that can be put out by you. Each of them are located at the bottom of each tower in that area. They do look like forge fires to me.

This video shows where the flames are located, but they are already extinguished.