Smelter Demon is an optional boss in Dark Souls II, residing in Iron Keep. If you came to the conclusion that is the right time to defeat him, yet you need the edge to do that, read on.
First thing, obviously, avoid his attacks at all costs. Smelter Demon usually strikes in twos, so be prepared to roll and avoid him. His sweeping attacks are massive, and cover a large area.
You’ll have to hover around his back, mostly. That’s where you’ll be striking him. Given the opening and the positioning that Smelter Demon does after his combos, the back is the place with the highest chance of a free shot.
Obviously, you’ll have to roll to avoid his attacks. But a fair warning: Smelter Demon likes to delay his attacks. It might take some time before you get it, but you will. Just gain the momentum by calculating his moves (which often come in pairs of two) and roll to avoid his attacks.
Another thing: when you hit him until his health is just below 50%, he’ll coat his weapon in fire, making this fight just a bit more difficult. Now he can one hit you, if you’re not careful enough; his attacks will shoot a fire of line. Use extreme caution, because you’ll become volatile and not in a good way.
Obviously, the Smelter Demon is resistant to Fire. He has some weakness to Poison and Lightning, so the right weapon upgrade might be just what you need. Prolonging this fight is pointless as with every minute, the chances of you becoming another matchstick for his massive burning weapon to light, increases with every second.
You might want to use a shield with high fire resistance, like Gyrm Greatshield. Shielding yourself with a shield from any of the Smelter Demon attacks is a good idea, though, you’ll sacrifice mobility by using one. Going bare (without a shield) will give you more speed and mobility, which is also invaluable in fight like this one.
Though it may seem like there is a secret strategy to defeat him faster, there is none. Your rolls and you're staying behind him when he’s winded after his attacks are only things that you should know, essentially. Use this knowledge to decimate and eliminate him.
