After fighting the Dragonslayer Armor, head through the newly opened passage. Just past the gate, go right where you found the Titanite Chunk on the balcony below. The path forward is the fast path to the bonfire. Here, you will find a corpse with a key to the Great Archive and the swords of the Gotthard twins. Use the key to open the gate ahead.
Immediately after that, go inside and run to the mage at the end of the corridor. Don't let him attack because he does a lot of damage. The faster you get to him and throw him to the ground with a few hits, the faster he will run up the stairs. Keep an eye out, though, because it can rain crystals on you.
For now, go to the corridor to the right of the entrance, where you spotted the enemy on the top floor. Do not let him deceive you and wait for another who will be behind your back. Only after you have eliminated them, collect the Titanite Chunk and head up the stairs to the left of the entrance.
In the hallway on the second floor, run after the lizard to get the Crystalline Gem and Shimmering Titanite. After you reach the fork, first go left, thanks to which you can collect the Soul of the Fallen Knight (watch out for the enemy that will be behind you immediately after you get close to the object).
Then, walk to the end of the corridor. On the right, behind the barrier, there is a Titanite Chunk. There will be another debris next to the enemy jumping down from the ledges. Turn around, where you will see several opponents who are looking to the side, next to a vessel with wax. They are not overly complicated. You should only be careful with the latter, which casts and slows down the wax (you won't be able to run and dodge for a while). After you defeat your opponents, change your appearance by dipping your head in wax.
Note: Dipping your head in wax will help you in several places in the archive. It protects you from damage and curses caused by purple hands sticking out of shelves and out of the ground.
Before leaving the room, head right (with the wax vessel behind you) where you can climb up the stairs to reach the ledge above. There you will find a Titanite Shard. And finally, go to the narrow corridor between the books on the left side. There you will find a knight with a spear. Lure him into the room. Watch out for his claps, as well as for his charges. After you defeat him, go to the room he was guarding and collect the crystal bell and the Titanite Chunk right in front of the entrance.
Return to the room where the wax was and enter the dark room to the right.
There are two lizards inside, killing them is rewarded with double Shimmering Titanite, Chaos Jewel, and Shimmering Titanite. On the wall is the Soul of a Nameless Soldier. Please note - if you do not cover your head in wax, you will be attacked with purple hands from the shelves. They deal damage and curse. If you dipped your head in wax, you will pass without any harm. There will be a lever next to it. After you take it out, you will reveal a small room on the left. Inside there are Power Within and Witch's Locks.
On the second floor, on the left side, there is an enemy and a Titanite Shard behind him. Collect it quickly, because there is another enemy in the center. After you defeat both, leave. You will find yourself within the spell range of the two-crystal Sage. This is why you must quickly kill the lizard (two Shimmering Titanites) and turn towards the exit to collect the Titanite Chunk on the right and hit the stairs. This will open the shortcut.
Then run to the balcony and dodge the spell. On the left you will find two Homeward bones. Before going to the sage, climb the stairs on the left flank with one opponent in front of it. On the second floor, there are two more opponents and a vessel with wax where you can dip your head. In addition, there is a Titanite Chunk on the wall.
After you go downstairs, you can go to the lever in the center between the bookshelves.
Climb the stairs to the right. Try to lure two opponents down, so that you will be out of reach of the spells of the Crystal Sage. At the top of the stairs, kill the small mage and attack the lizard. After a while, she will teleport to the bridge on the other side.
Note: You can also get to the balcony, and go around two opponents to get up the stairs to the balcony below.
Continue up the stairs on the left. On the second floor, watch out for more than three opponents. First, lure down the smaller one, thanks to which the bombs of other enemies will not be able to reach you. Walk forward a little to find a trap in front of you (make sure your head is in wax), that is, several hands sticking out of the ground. In addition, there is a magician on the wall - watch him, because it is very risky to kill him without the protection of wax. There is a Titanite Shard in the corner.
Ahead from here, there is a strange kind of wall. This is an illusory wall through which you can reach the room shown in the screenshot. There is a very fast enemy inside, during the battle with which you should always try to keep him in sight, in front of you. At the same time, dodge and go behind him to strike. Rely on your dodges, not the shield, and hit after the opponent has performed a combo or strong push (dodging will allow you to be behind him). For this battle, you will receive his Knight Set. You can exit to the balcony on the right, where you will find a soul next to a corpse sitting on a chair.
Exit the room and go to the mage on the bridge (before that, go left, where you found the Titanite Shard behind the bookshelf). Jump down and deal with the mage, attacking him until he disappears. He will then appear in front, allowing you to quickly rush towards him and end his spellcasting. This will make him leave. Keep repeating this until the mage disappears and leaves the Crystal Scroll.
Go to the place where you jumped off earlier (there is a knight at the end, but don't worry about him). You will find a lever here that opens the gate to the small wax pool. On the corpse on the chair, there is a scientist's ring. On the other side, up the stairs, there is the Shriving stone.
Now head back to the bridge where you can jump off the left side. You will find yourself on the bookshelf. There is a lizard at the bottom - for the kill, you will be rewarded with two Titanite shards. After you jump down, you will find yourself in the room that you crossed at the beginning, where there are four opponents and a vessel of wax. If you activated below the place where you could attack the crystal lizard a second time, go to the balcony opposite the wax vessel (screenshot). By pulling the lever, you will open a passage between the books, at the end of which there is a Titanite Chunk.
And finally, return to the bridge and go to the side where the first balcony is - leave the balcony behind you, go between the shelves, up the stairs and follow the two opponents on the right, as well as the magician at the end. Once you kill them, you can jump down to the shelf below where you found the Titanite Shard. Heal to maximum health and run to get to the shelf below. Once you do the long jump, you will find yourself on a platform where there is a corpse with Evelyn's crossbow.
Return to the bridge where you will fight the lizard again. Take a walk to the other side. Inside, there is a lift to the first room. The path outside will lead you to the rooftops. Before going there, you must get more wax to eliminate the enemies above. On the wall, there is the Soul of the Fallen Knight. After you climb the stairs (before that, open the chest with three titanite shards), where you will meet the lizard (Shimmering Titanite and Exquisite Gem) and collect the Bite ring.
Go to the rooftops.
