Jade Dugout is part of the Mines of Chosain cluster, along with Den of Crowmen and Abyss of Kun Whu.
Boss is mostly killed using mechanics of the instance itself, rather than dealing direct damage to him, which makes the instance more fun. He has a huge HP and deals massive damage which makes you use mechanics rather than pure nuking.
There is several things you should be aware off:
1. Trash mobs in form of guards. There is 2 kinds: melee and magic, magic are priority to kill.
2. Slaves. They are used to activate the boss. You need to talk to them to 'reveal' them. Some are real slaves who run off, some are loyalists that will attack you and one is actually a boss in disguise.
3. Black powder urns. When you right click them, you activate a fuse and they explode after 4-5 seconds, dealing large AOE damage. They are the key to defeating the boss. After the urn is used it won't respawn until instance is reseted. If you are caught in the blast it will hurt you, alot.
4. Stun bombs. They are located inside crates which are scattered arround instance. Every person in party should have one before you start boss and equip it in their quickbar. They should be used on boss to stun him for 7 seconds (target boss then click on bomb in your quick bar). After the bomb is used it goes on a 45 seconds cooldown. To be able to use bomb you need to be 5-15 meters from the boss, if you are closer than 5 or further than 15 they wont work. Notice that sometimes bombs bug in quickbar (you click and nothing happens even if you get the correct distance). In that case they should be used directly from inventory.
5. Pool in the back of one of the hallways. When you jump into pool the instance resets.
Start by clearing the main room from trash mobs and collecting bombs for everyone in the party.
After the room is cleared assign a bomb order. Everyone but main tank should be in the rotation (although main tank can use the bomb like anyone else it will be difficult cause of the distance needed for the bomb to work).
Tank should start talking to slaves until he reveals the boss. He should Irritate boss and go stand near one of the Black powder urn. Boss will follow tank to the urn. After boss comes to the urn, 1st person uses a stun bomb on him. Boss is stunned for 7 seconds and tank right click on urn to light the fuse and run from it. Since fuse is faster than 7 seconds it will blast the urn and hit boss for ~8% of his health. Boss will be knocked down. Irritate again and lead to another urn to repeat process.
Sometimes boss will stop and cast a spell (think its called Trembling Rocks but not 100% sure) which will send down rocks from the ceilling on to head of someone. Casting is fairly long so scatter out and move from the spot where rocks are droping (need to have particles activated to see them).
At each 25% (75%, 50%, 25%) boss goes into hide again, new bunch of slaves appear and you need to find him again by talking to slaves. At last 25% 2 adds will also come with the slaves so take care of them fast. Talk to slaves as fast as you can since boss will heal up while he is hidden. You can have 2 people talking to slaves which is a bit risky but it might be worth it (you will reveal boss faster so he regenerate less HP).
Since each urn takes ~8% of boss's HP after first 3 urns boss should be ~76%. At that point hit the boss with all you have since you dont want to waste exploding urns (cause of the limited number of them). Notice that you can stun boss and then hit him, which is good choice since boss deals massive dmg. This should be also repeated if the boss is close to 50% and again at 25%. Dont be affraid to nuke 5 or 6% off boss since you can stun him for 35 seconds (5 persons x 7 seconds per stun).
If you dont waste any urns and dont take too much time revealing boss you will have enough urns to kill him with just exploding urns. Save 4 urns (32%) or atleast 3 urns (24% plus nuke whatever he healed at the end).
If you used all of your urns and boss is not dead, then you will need to tank and spank him. Notice however that last 25% must be done in total of 5 minutes else boss enrages and you are in trouble. Tank should prolly save his bubbles for the end of the fight.
What is important is to not waste any urns. If you are not sure of the positioning, just dont activate exploding urn, move the boss to next place and someone else will be able to stun boss soon enough.
The key in this fight is coordination and not panicking. Use voice chat if possible and if not, then write in chat numbers as you use stun bombs so that next person in rotation can prepare to use his.
To activate godslayer mode you must not kill any trash mobs before you activate boss.
A good tactics is to clear the room when boss hides at 75%. He will fully heal untill you clear room, but rest of the fight should be much less stressfull.