Well here we are, back at Lothric, almost where we started, except now the sky has gone a horrible shade of orange and there's an ominous dark circle in the sky, so everything seems to be going well. We're well on our way to the last Lord of Cinder, but first we've got to get through this area and the angry suit of armour boss at the end of it. This guide will help you along the way, telling you how to get past the dragons and open up all the bonfires, but if you want to find all the loot you're going to have to do some exploring by yourself.
After you defeat the Dancer of the Boreal Valley you'll get a bonfire for her, which is technically part of the High Wall of Lothric area. From that bonfire go to the statue at the back of the room and interact with it to trigger a cutscene, raising concerns for whoever designed a mechanism in which a statue has to cut it's own neck and bleed into a bowl just so a ladder will drop down. Anyway, the ladder has now dropped down, and you can climb up it.
At the top you the path branches. Right is a dead end, left will take you to the Consumed King's Garden, but for Lothric Castle we want to go forwards. In this room there's a red eyed knight and a robed cleric who'll heal him (and as a side note: you're going to run into more pairings like this, and it's a good idea to take out the robed healing dudes first). Run out of the room to the right and you'll find yourself in front of some steps. Go up them and run along the corridor here, avoiding some more knights, and you'll reach the bonfire.
From the Lothric Castle bonfire go out of the room to the left and out. You'll end up on the castle battlements. Follow them around, up the stairs and keeping vaguely left–ish along the wall, past many hollow enemies of various sizes. You'll shortly come to more stairs leading up, with some small wooden barricades at the foot of them. Go up these, and keep going, until you come out to a ruined courtyard. The new bonfire is on the left.
Appears after you defeat the boss Dragonslayer Armour (unclear if anyone is actually in the armour but probably not).
So once you're at the Dragon Barracks bonfire you can turn and go up the stairs behind you, which will lead you to a bridge. There's a big dragon the other side of the bridge, which will probably not have escaped your notice. As you move over the bridge another dragon will fly in and the two will start breathing fire. It's almost impossible to run all the way through from the bridge, so instead, at the very start of the bridge, drop down from it onto the walkway below. Keep heading left to an open area where a bunch of hollows will run at you. Go up the stairs and left, into the building. The room you're in now is directly beneath one of the dragons, but you can't quite get to it yet. Run straight forwards towards the open side of the building, drop down, and sprint straight across to the doorway opposite you. This way you'll hopefully avoid the dragon fire. Or at least most of it, anyway.
The building you're in now is really dark, but there are some hollows lighting it up by throwing firebombs. They're only trying to help! On your right is a ladder, so head on up there. A bunch of hollows will run at you from various places, so deal with them before noticing that you're right by a dragon's foot. Wallop it a few times and an abyss creature will spawn out of it. Once you've killed that the dragon itself is dead, and you get a nice load of loot in return. This also triggers the death of the other dragon, (although it's body doesn't evaporate), so you no longer have to worry about being burnt to death.
Now, from where you are, standing where the dragon's foot used to be, go up the stairs from the platform you're standing on. You'll run into more hollows chucking firebombs, but once you get to the top you'll be able to turn left. You're now on the other side of the portcullis that was closed before, and there's a lever in front of you that will open it for a smoother run through. Drop down to the right and head up the staircase opposite, then right out onto a courtyard with the boss fog wall in front of you. On the wall to your left is a ladder up to the roof. From this roof you can drop down onto the other dragon's foot and get some extra damage, or stay on the roof and cheese it with projectiles, but there's also a bit of broken wall on the left too, in case you didn't feel like jumping off a roof. Job done; rewards claimed.
The final bit before the Dragonslayer Armour boss area is a bit of a pain. You've got a lot of enemy mobs, as well as two dragons, to contend with, but there is a lift that you can open between the boss area and the Lothric Castle/Dancer of the Boreal Valley bonfires. Start at the Dragon Barracks bonfire and run over the bridge and to the main staircase. Go up and to the left and you'll come out in front of the boss fog wall. The lift you want is on your left, and takes you down to that first room with the red eyed knight and his pal. Nice one.
From the Dragon Barracks bonfire run to the end of the bridge and drop off here, onto a ledge. The Undead Bone Shard is here. You'll then have to drop from the ledge and make the trek back the long way round through the buildings, but it's worth it.
This is another Braille Tome to chuck at Irina of Carim back at Firelink Shrine. In the same building where you can attack the second dragon's foot, described above, you can turn around and go up a short flight of stairs to the second level, where a curled up body has the tome.
Buy the official Dark Souls 3 Guide now.