The run to the Blue Smelter Demon was the worst, but I also didn't realize that it was designed to be done co-op. One of the most difficult runs to any boss ever and the boss itself was no joke. But I did it. Solo. No shield.I agree. The whole Iron King DLC put me off the entire game tbh. The bosses were super hard for me, great I can live with that the Souls games are supposed to be hard. But running gauntlets each time to face the boss again was just too much and felt like it was just there to annoy the hell out of you.
Never even tried the 3rd DLC.
As far as running gauntlets to get to a boss, that was the norm with Demons Souls and Dark Souls 1. FROM were actually quite generous with DS2 and Bloodborne, often having an easy run to the boss from a bonfire/lamp(Fume Knight was literally a 15 second run from bonfire to boss). That made it a bit more 'shocking' in certain parts where they didn't do this.