Dungeon of the Forgotten King

You wake up suddenly in a dark, unfamiliar place. You realize that you are in an open cell inside a dungeon, without your things, dressed only in rags, and no matter how hard you try, you don’t remember how you got to this dreary place. As you step out of the cell, you find a campfire that never goes out, a spectre that seems harmless and 3 mysterious altars, as well as a door that leads to deeper parts of the dungeon, from where you perceive the shadows of hostile beings. You decide to set up camp in this room, as an unknown power blocks magic and seems to prevent enemies from approaching.