The Duke's Archives are basically a huge library building with many levels. In addition there is a prison area in one of the towers and there is a Crystal Cave section. The main enemies you will encounter are the Undead Crystal Soldiers in the library, and the Serpent Soldiers in the prison.
- This area is locked until you have placed the Lordvessel.
- The Undead Crystal Soldiers you will encounter deal a lot of damage if they hit you, hitting them with pure physical damage weapons like a Black Knight Greataxe will only deal little damage.
- Big Hat Logan is in a cell at the bottom of the tower. A key is needed to free him. (See walkthrough for details)
- You cannot slay Seath The Scaleless the first time around. It's recommended to equip a Ring of Sacrifice or Rare Ring of Sacrifice before he inevitably kills you so that you can keep your souls and humanity.
- After Seath The Scaleless killed you, you will respawn at a new bonfire and you cannot use Homeward Bone or the miracle Homeward to come back to the last bonfire you used, you will be put into a frozen prison in which you need a specific key to get out of.
- Using the Ring of Fog (or equivalent magic) throughout most of the level can help tremendously for avoiding getting pinned or blindsided by arrows when trying to clear out the melee Crystal Soldiers. Note that the Channelers can still see you at quite a distance with the ring, however.
- Big Hat Logan (after you freed him from his prison cell).
Getting to the Archives
To get to the Duke's Archives, you need to turn left instead of going straight from the first Bonfire in Anor Londo. You'll have to kill a Sentinel to take the stairs up to an earthen path leading up. The path ends in a gateway which is inaccessible unless you have obtained and placed the Lordvessel. Go down the hallway to find an Armored Tusk. Unlike the one you dealt with in the Undead Parish, this one isn't near a fire for you to lure him into. You'll have to do this the hard way. Getting behind him is fairly easy, as is avoiding him, since walking backwards often results in his attacks falling short. Just keep chipping away with one or two attacks, and eventually he'll go down. Alternatively, if you can hit him with 3 Poison Arrows from your bow's max range and get your shield up for his initial, the fight is much easier.
Turn left and there'll be another one for you to deal in the same way, except Poison Arrows can't help you here due to the corner. When this is done, you'll find a large open room with a lever-activated lift at the end and a bonfire to your left. Light the bonfire and rest by it, but don't bother kindling it, as this won't be your base of operations for long. When you're done, pull the lever and take the lift up.
Proceeding on the lever-activated elevator you will come across 3 Undead Crystal Swordsmen (one is hiding) and 1 Undead Crystal Archer, be careful to not be hit as their damage it rather high. Using a strong shield with high stability is advised. If you have the Artorias of the Abyss DLC, a Crystal Golem will be added. Killing it will cause it to drop the Broken Pendant, allowing you to access the new content in the Darkroot Basin. Further on in the next room will contain Channeler, 3 more Crystal Undead Swordsman and another 3 Undead Crystal Archer. The Swordsmen are easy to lure out one by one. When you go into the room use a shield with high magic resistance as now is the time to use it. Upon attacking him he will teleport further back into the library so make sure to get the most damage him as quickly as possible! Once all Undead Crystal Soldiers are dead on the bottom floor, make sure to check under the staircase for a Large Soul of a Brave Warrior.
Head up the staircase and be careful of one more Undead Crystal Archer. Go to your right and you will come across a balcony with a charred corpse containing a Twinkling Titanite. Be wary he is guarded by a total of 4 Undead Crystal Swordsmen. They can more or less be pulled in ones or twos. Further on the right corridor, you will come across a chest at the other end of the hallway, be careful its a mimic! It drops a Crystal Knight Shield when killed. Go back to left hand corridor and at the end you will find a chest with another Twinkling Titanite. Take the elevator up.
The elevator drops you into a semi crystal covered room with one passage out. Be wary there is a NPC in Crystal Armor here that is waiting for you. He does not respawn and seems to dislike fire damage. Gives 3000 souls when killed. Proceeding, you come across stairs leading up with a Crystal Lizard in the middle. Just rush him and he stops in the middle of the stairs to phase out and you can smack him with any attack. At the top of these stairs is a Fog Gate leading to your first encounter with Seath the Scaleless]. You cannot really hurt him, since he will be instantly healed. You will die and respawn at a new Bonfire in a circular prison area. Note that if you accidentally walked in and are facing Seath, he will not immediately attack you, and you can actually leave through the Fog Gate you came through. Go ahead and do this if you want to go spend your souls and/or humanity before losing it to him.
After dying on the above mentioned "top floor Seath" encounter you are resurrected behind bars in a cell with another bonfire in what appears to be the basement of the Duke's Archives. It's not a bad idea to kindle this bonfire, as you could be dying a couple of times in this area.—There are three Crystal Soldiers at the end of this cell who respawn. You must kill a Serpent Soldier who is leaning on the bars to your cell but on the outside. Once killed, loot the key to the cell through the bars and open the door.
There is a pathway off the top of the spiral staircase that can be dropped down from to get the Maiden Set of armour and White Seance Ring, and one of the cells has a drop that will lead you to an extra key which takes you to a soul. Just loot all the cells you can on your way down.
The Archive Tower Extra Key can be used on the other locked door in your original cell. From there you can drop down to loot the corpse of some souls and then down again to the gramophone to turn off and get the Archive Tower Giant Door Key. This key will open the door at the top where the Serpent Soldier first ran off to when you got out of the cell.
To leave this area you need to go left from the bonfire and up the ladder, but you won't be able to open the massive door until you get the Archive Tower Giant Door Key. To get this go all the way to the bottom of the spiral stair, and up the ladder immediately visible at the bottom of the stairs. There are two Snake-Warriors here and one Snake Mage, so be careful; these are tougher than the ones at Sen's Fortress! The lever for the siren is also here. No need to turn off the Siren/Gramaphone if you enjoy its creepy melody. It only causes the Pisaca to leave their room on the ground floor. On your way back, don't forget to kill the crying Pisaca, who will drop the Bountiful Sunlight and Soothing Sunlight miracles and humanity. Talk to Big Hat Logan, who's gotten himself in another pickle, as well. You will need the Archive Tower Giant Cell Key to free him, which can be found in the library area.
Archive Area (Return)
Go down the hallway to the balcony. On the right is a Undead Crystal Swordsmen, and on the left down the way is a Undead Crystal Archer, so watch your back. There is a Undead Crystal Soldiers guarding the archer to the left in ambush. Exit the balcony back into the archives. For clarity's sake, the chamber you have just entered will be called the east chamber, and the chamber you will reach down the hall to your left will be the west chamber. The side you enter on will be considered the south side, and the side opposite the north side.
If you don't care to explore go up the stairs and up the ladder. You will find yourself on a walkway with some Crystal Soldiers leading back to the archives you first entered except now another wing and floor has * opened up joining the previous floors you had access to. (EDIT: not done yet but feel free to fill in and please confirm it)
There will be a Channeler down the hall to your left. and a channeler above you, who will fire but often whiff against the columns in the area. Be careful not to follow the Channeler to your left too far, as there is a Undead Crystal Archer, and Undead Crystal Swordsmen further down to the left. After taking these enemies out, go up the stairs to your right and clear out the Undead Crystal Soldiers, there. Then go back to the middle of the staircase and turn the wheel. This will spin the staircase around, giving you access to new balconies in the archive, and giving you a shortcut to the very beginning of the Duke's Archives, and the Bonfire that was there. We're just about to get to another bonfire though, so don't worry about that right now. Grab the Twinkling Titanite from a chest on the right of the area, then go back the way you came from.
Go back to the entrance you originally came in from in the east chamber and this time go down the stairs to the left of the east chamber. You're going to be taking out quite a few Undead Crystal Swordsmen and Undead Crystal Archers, so keep your shield up and be aware of archers at the ends of hallways, as their arrows really hurt. All the way at the bottom of the area you'll find a bonfire on a balcony to the far right of the room. This is a nice base of operations, but you've just slogged through a whole load of Undead Crystal Soldiers, so unless you're really low on Estus, it might not be the best idea to rest just yet. Time to go back up and take out that annoying channeler right at the top of the east chamber. climb the stairs until you reach the entrance you used initially, then go back into the west chamber. Turn the stairs in the west chamber, then go up them to the highest level you can get in the west chamber on the south side. Go back into the east chamber and you should see a gap in the railing opposite the channeler we want to kill. This will allow you to jump down onto stairs leading right up to him. Make your way up to him and kill him, but be aware that he will teleport to the other side of the chamber, where you originally jumped off from. To get back to him you'll have to turn the stairs around, or kill him with ranged attacks. Once he's dead go back to where his original post was and turn right to find a chest with the sorcery Strong Magic Shield in it. Done!
The next step is to go back onto the stairs you just used and turn them around so that you're going downwards towards the north side of the room. You should see a bright doorway at the end, with a Undead Crystal Archer annoyingly placed on a ledge opposite you. Kill him with ranged attacks then slide down the ladder to get to ground level. The lever you find at the bottom of the ladder will open a secret door to the main ground level area of the east chamber, near the bonfire. The smaller room contains a chest with an Blue Titanite Chunk. Leave this room an proceed further into this semi-secret area to find a room containing another lever and a two chests. One chest is a Mimic that drops an Enchanted Falchion, and the lever will lower some stairs to go further down. Before you go, though, turn right past where the Mimic used to be to find a hidden chest containing the Crystal Ember. In the same room you will also find a chest with the Archive Tower Giant Cell Key which you need to free Big Hat Logan. Lastly in the far left corner of the room is a lever to lower the stairs that will allow you to proceed.
Freeing Big Hat Logan: Big Hat Logan is sitting in the Giant Cell of the Archive Tower, which you find behind the group of Pisaca on the bottom of the prison. You will need the Archive Tower Giant Cell Key in order to free him which you will find in a semi-secret area in the archive area (see above). After you have either killed or evaded the Pisaca you can open his cell and free him. As reward he will reappear in the library are and sell you the powerful crystal spells. But before you leave the cell, don't forget to pick up the Fire Keeper Soul on the body at the end of the Giant Cell.
Getting to the Crystal Cave
Almost done with the Duke's Archives now. Go through the white light and find yourself on a precarious wooden platform. Don't step forward, go to your left and take the ladder to avoid the damage. At the bottom, have a look around. The scene will look a lot like the area in front of the Hydra in the Darkroot Basin, except sunnier. You will see a lot of Crystal Golems, and if you followed the Siegmeyer of Catarina storyline, you'll see one Golden Crystal Golem in front of you. Bait it towards you with an arrow and defeat it to reveal Sieglinde of Catarina. Have a chat with her, then move on. Further in front of you there will be a full Crystalline Set, and to the right there will be a chunk of Blue Titanite. You absolutely don't need to kill all the Golems in this area, but if you tackle them with patience they're fairly easy souls, and because of their high aggro not tackling them on your terms might cause problems for you down the line In any case, head down and to the left to the huge crystal pit to enter the next area. Well done!
Duke's Archive revisited
After you have defeated Seath the Scaleless in the Crystal Cave head back to the top floor where you first met Seath. The room now contains a chest with the Large Magic Ember and on a body you will find the Soul of a Great Hero.
Chest on top of the Book Shelf
You will notice there is a chest on top of one of the bookshelves, in the room with the first Channeler, which seems impossible to reach. In order to reach the chest, you need to drop off of the turning staircase above. The timing is hard to get right - it's important to start early as the momentum of the turning staircase seems to keep your character moving sideways as you fall, most often causing you to hit the floor on the far side of the bookcase. Missing appears to be guaranteed death, even with Fall Control active.
This chest contains the Avelyn crossbow. See that page for more information on getting to the chest.