Iron King, not Ivory. I'm in the dumb cave where your only options are a clusterfuck of zombie knights and projectiles, or run down a hallway of exploding fireballs, and then fighting a buffed Smelter Demon, already my least-favorite boss in the base game. It wouldn't be too bad if not for the damn recycled boss. Really, recycling this asshole? I do not like Smelter Demon. I don't think it's mandatory here either, but this is just reminding me of lots of dumb shit.
Am I the only one who enjoyed fighting the Smelter Demon? Thought it was a pretty good boss fight.
He's optional. However...killing him gives you a really nice mask that bathes you in water uping your fire resist significantly. I think it has the same effect as those Jars in Iron Keep.
Plus
Using this Smelter Demon's Soul you can get its unique blue flame sword that is magic based.