King's Passage can be reached by travelling to the Central Castle bonfire and traveling through the left (lower) tunnel to the three way split room and entering the large doors (require the King's Passage Key to open). Read up on how to obtain this key and opening the doors in the Drangleic Castle section. For those heading onwards, head down the small hall to the large storm lit passage ahead. Look to your right as it widens to spot an Alluring Skull to pick up off the ledge here. Four of the statues in the long rows will animate when approached or attacked and are quite dangerous. Taking them out with ranged attacks as they get up is the best strategy if possible. The second statue on the left, the third statue on the right, the sixth statue on the left and the fifth on the right are the ones that animate. A syan knight blocks the mist door at the end of the room that leads to the boss fight. Before heading through the door, look behind the nearby pillars to pick up the Twinkling Titanite and Soul of a Proud Knight off the nearby skeleton. When you are ready, enter the mist door.
Boss: Looking Glass Knight
Personal Death Count: 4
Leap Attack: The looking glass knight will hunker down and then leap towards the players location, slamming his sword down when he lands. This causes decent damage and can lock the player against a wall if the player is backed up against one. Roll to the side to avoid the attack and try not to be backed against a wall to prevent being boxed in.
Shield Bash: The looking glass knight can peform a relatively slow shield bash that deals damage and staggers the player. He normally only does this if you are very close to him. Roll backwards when he pulls the shield back.
Slash Combo: The looking glass knight will raise his sword arm slightly and then swing it in a slow arc towards the player. This can be extended into a combo of two more hits sometimes so be careful. Roll backwards to avoid this slow attack (and roll back again if it is the chain).
Spin Slash: This attack can be imbued with lightning or used regularly. If he does imbue it (holds his arm above his head while lightning crackles into it) it will deal a large amount of damage. He will then spin around in a circle with a large cutting arc. Roll backwards when he starts to spin to avoid this.
Sprint Thrust: The looking glass knight will hold his sword out to his side (horizontally while pointing towards the player) and then will dash towards the player. This can cause nasty damage and can take you by surprise if you are too close. It's reach is quite long as well. Sideways rolls are the best method to avoid this attack.
Lightning Blast: He will imbue his sword with lightning by raising it overhead and then slam it into the ground in front of him, releasing several pulses of lightning in a line in that direction. Roll or sprint to the side to avoid this attack.
Lightning Wall: The looking glass knight will raise his sword and imbue it with lightning and then peform the first slash combo swing, causing a curved wall of lightning to emerge from his blade. Sprint to the side (or roll) towards his left side to avoid this attack.
Summon Phantom: The looking glass knight jams his shield into the ground in front of him and charges his energy. After a few seconds, a phantom or invader will emerge from the shield and join the fight. The only ways to stop this is to smash his shield in battle with heavy melee attacks or deal enough damage while he charges to stagger him.
If possible, you should summon NPC Benhart of Jugo (his summon sign is to the left of the mist door) to join you in the battle. This makes the battle far easier to deal with. If this isn't an option, make sure you have a decent health total as his hits are quite heavy (use the ring of binding or health rings to increase your health total so you can survive a hit). The main threat of the battle is his ability to summon phantoms and invaders into battle with his shield. Melee players should try and shatter the shield if possible and stand in front of it as he summons to quickly deal with the emerging enemy. Ranged characters should get a good angle on where the enemy will emerge (you can auto-target the enemy before it emerges) and quickly open fire when they do. Killing them off before the boss completes his recovery animation and begins attacking again (see the video for examples of this).
The regular attacks of the boss are relatively slow, but damaging if he catches you. The slowness of his attacks should give you plenty of time to heal up or reposition yourself. Melee characters will want good physical and lightning defense (on shield and armour) to deal with his heavy attacks, while ranged characters will want to avoid them at all costs. His lightning attacks are quite predictable but getting the timing down can be tricky (especially on the lightning wall attack). I always found rolling to the left side far more effective to dodge the attack. Another thing to note is that his shield can actually deflect magical attacks, potentially redirecting them towards you, so casters will want to circle left around him to avoid hitting the shield as much as possible. After enough hits and probably a few heals, you should eventually take him down.
Once that eventful battle is over, head to the far end of the area and walk past the lift panel. You should see a chest nearby, open it up to retrieve the Soul Bolt sorcery, Spell Quartz Ring +2 and a Bonfire Ascetic. Return to the lift panel and descend. In the room at the bottom you will see a passageway with roots emerging from it. Follow the path until you come to a small lit up room. Some vines on the side of the room can be destroyed to reach a corpse holding a Green Blossom. Return to the other exit out of the room and follow the tunnel once more. The tunnel will emerge out into a large underground tunnel with the first bonfire of the Shrine of Amana directly in front of you. Our path continues on in the Shrine of Amana section.