Dark Souls 3: The Ringed City is a much bigger expansion than Ashes of Ariandel, and it has a few surprises up its billowing sleeves that you might struggle to find. One of those is a hidden boss who'd be better off staying hidden, if you ask me. My pride as a Dark Souls expert is gone at this point. It’s definitely one of the harder fights in the game.
To get there, you’ll need to be a good chunk of the way through the DLC, so turn back if you’re worried about spoilers.
From the Shared Grave bonfire, head across the bridge and take care of the ‘problem’ if you haven’t already. Head upstairs and look right to find the Ringed City Wall elevator shortcut. Halfway through, you’ll need to jump into a doorway that passes by. I recommend heading all the way up to unlock the door to the Ringed City Wall bonfire first. If you die, and you definitely will, it’s going to be home base for all your attempts.
Once you disembark in the elevator shaft, go left and head down the stairs. You’ll enter a circular room lined with statues. Swing at the statue immediately to the right of the glowing loot to reveal a hidden path. Continue down the stairs and head down the ladder. Things are about to go down (ha ha—but really, you need to go down some more).
Pick up the items and summon help if you’re feeling nervy. From here, you’ll just need to drop down into the deep, dark hole at the far back of the room. The rest is all you. Best of luck, Ashen One.