The Archdragon Peak is an optional area in Dark Souls III, and it’s also a place where you can get some sweet loot and armor sets. First, you need to have defeated the Dancer of the Boreal Valley and gained access to Lothric Castle. From the Dancer bonfire, head up the ladder, and proceed to your immediate left. Get onto the elevator behind the knight, and it’ll take you to the lower area.
This area is full of the snake/tentacle-head enemies, so either kill them with Firebombs, or run past them. Your goal is to run straight past them until you reach a small clearing with three knights. You can run past the knights, and go down the flight of stairs to face Oceiros, the Consumed King. After defeating him, simply follow the linear path down where you’ll face enemies with bandaged bird heads. You’ll come to a room with a dead end, and a chest at the end. In the middle of the room, you’ll see a dead knight sitting upright. Examine his body to get a new gesture. It’s time to head back to the prison in the Boreal City.
From the first prison bonfire, take the elevator shortcut that would lead you to the basement where Karla was locked up, and the area with the women with the fire brands. Instead of heading into the basement area, once you get off the elevator, you should see some dead bodies sitting upright, staring at a structure in the distant night sky. There’s an empty spot next to one of the bodies. Go to the empty spot, and use the gesture you just looted off the knight. A cutscene will play, and when you wake up, you’ll find yourself in Archdragon Peak.
Be sure to check out our Dark Souls III wiki for more tips and tricks.