For those looking for the location to upgrade the fire ability.
The frame of reference will be the
Estate of the Urn Witch Door.From the door head down and back right all the way to the lift that brought you to this area and takes you back up to the Lost cemetery.
After using the lift and exiting out of the lift room at the top go down one room and the door to the left will have cobwebs over it which you need to use your fire to get rid of. The upgrade fight is in this room.
Once again the mini-boss ain't too difficulty and if you die you have the option to simply try again, spawning in that room so there's no problem if it takes you a few tries.
Easy video here of the 60 seconds route to follow for those who prefer that for the location
