In order to enter Sunken Temple of Qarn, reach level 35 and accept the quest "Braving New Depths" from Nedrick Ironheart in Vesper Bay. While you can get the quest at level 32, you will be unable to enter Qarn until 35, unfortunately. This is an optional dungeon and not part of the main storyline.
As you travel through the ruins, you will find rooms with objects on pedestals. There are four in total, which include The Helm of Might, The Gem of Affluence, The Flame of Magic, and The Fruit of Knowledge. These will be required later in the dungeon to access most of Qarn's treasure coffers, so try to grab all of them. You will also encounter doors that can only be opened by killing a specific monster on a switch. This is explained more in the Notable Trash section.
Within the first few trash pulls, you will start fighting groups which contain a Temple Bee. These should be the primary DPS target. If they are alive too long, they will use Final Sting, greatly damaging and possibly killing your tank.
There is also a Qarn Facer, which you will encounter just after The Helm of Might. I'm not sure if it's based off of health or time, but he will run away shortly after the pull is engaged. He will reappear periodically throughout the dungeon and, when you finally kill it, will drop a treasure coffer.
Finally, after the first boss, there will be rooms where you encounter stone heads called Avoirdupois. In any room you find them, there will also be a switch, similar to the switches on Teratotaur. Killing the Avoirdupois on the switch will open a nearby door, as well as preventing the enemy from reviving. To be certain they are on the switch, do not kill them until the switch stops glowing orange. If it is killed anywhere other than the switch, it will ressurect a few seconds after death.
The Teratotaur encounter contains multiple instant death mechanics, so each party member needs to be aware of their surroundings and avoid tunnel visioning. On the pull, Teratotaur should be tanked near the back switch, where the cement has cracked, facing away from the party to prevent Mow from hitting the group. The tank should dodge both Mow and Frightful Roar.
While dodging these two abilities, two Dung Wespe will occasionally spawn. If you are tanking near the back switch, they will spawn on top of you and should be easy to pick up. These should be quickly killed by everyone. If these are alive too long, they will attempt to Final Sting their target.
And, if that wasn't enough fun yet, Teratotaur will also start casting Mortal Ray, placing the Doom debuff on the entire party. Doom lasts 12 seconds, and will instantly kill you if it expires naturally. It can only be removed by stepping on the switch which has the corners glowing orange. To make this trickier, only one switch will be glowing at a time. While it could be a coincidence, I found that the switch that was glowing would change almost at the same time Mortal Ray is cast.
At this point, the fight gets hectic. Doom will start to be cast quite frequently, while the Wespe will keep spawning and need to be dealt with quickly.
The Temple Guardian itself will take nearly no damage while the Golem Soulstone on it's chest is alive. Killing it will cause the Temple Guardian to become stunned for a long period of time and allow the healer to catch up on healing. After the stun, the Golem Soulstone will respawn and will need to be killed again. This repeats until the end of the fight.
Onto the abilities. The Temple Guardian will nearly always be using cast time abilities which have ground indicators. This includes True Grit, Boulder Clap, and Rockslide. Everyone should be dodging ALL of these. The healer will be busy with the unavoidable damage and will quickly fall behind if these aren't dodged.
To summarize, dodge everything, kill the Golem Soulstone first, and try to stay somewhat close to the healer so they can AoE heal.
This is where The Helm of Might, The Gem of Affluence, The Flame of Magic, and the Fruit of Knowledge come into play. Each of the Pedestals has a small icon above the hole indicating which object should be placed into it. The helm is The Helm of Might, the strawberry is the Fruit of Knowledge, the diamond is the Gem of Affluence, and the fire is the Flame of Magic. Placing the correct object into the pedestal will open a hidden door, revealing a coffer.
A bit further in, and you will discover the Scales of Judgment. Choosing either the left pan or right pan will allow you to place any of the four objects on it. The clue to solve this is at the start of the dungeon. The Warden shows a flame on the left and a strawberry on the right. Replicate this with the Flame of Magic on the left pan and the Fruit of Knowledge on the right pan to spawn three treasure coffers.
The Adjudicator himself will cast a frontal cone ability called Darkness, which the tank should dodge. He will also cast Paralyze on a random player, which the healer should cleanse or, if you have a Scholar healer, the tank should stun the cast. While this is happening, Stone Heads called Sun Juror will spawn. Similar to the trash stone heads, these will revive unless killed on top of one of the switches. These do not have to be tanked, as long as they are killed quickly.
Another type of add, called a Mythril Verge, will also spawn. These are stationary and do not melee. Instead, their only attack is to draw a light blue beam through a random party member. A few seconds later, it will fire a laser in the same path, dealing heavy damage. Each Mythril Verge has low health and, ideally, should be killed by a DPS with strong burst.
Just when you start to feel comfortable with how the Mythril Verge works, it decides to screw with you. If it spawns with a large, black box around it, it will not fire the lasers. Instead, if will start Verge Pulse, a long cast which, if allowed to go off, will deal ~600 damage to the entire group. Not only that, but attacks will do reduced damage unless you are inside the black square, which will seal itself from entry when someone steps inside it. While this typically means only one person can go in, multiple players can enter if they run in at the same time. At least one DPS should quickly move inside when it spawns and kill it before it's cast goes off.
Around the time the Mythril Verge with black boxes start spawning, the Adjudicator will also start casting Creeping Darkness, which will deal unavoidable damage to the entire party. This makes Verge Pulse much deadlier if they start going off too frequently or at the same time.
The real fun starts when the boss is around 30% health. He will enter a soft enrage of sorts, spawning four Mythril Verge, which will fire lasers everywhere. These should be killed, unless the boss is almost dead. Also, when he spawns the Black Box Mythril Verge, he will spawn two instead. Both DPS will have to take one of these out.
Complete the Quest: Braving New Depths
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