The Dreadblades

I had some troubles with this quest not functioning as expected, or just being unclear, so here's how it should go for anyone struggling:

After arriving in Azsuna...

1. 
   
2. Sneak aboard the ship. Avoid land mines and patrolling dogs. Use Bribe on the First Mate.
3. 
   
4. Sneak along and around the beach, once again avoiding land mines, dogs, and now sharpshooters. (Also, do not stray too far from the beach. Can reset and send you back to stage 1, which is bad because Bribe will still be on cooldown).
5. 
   
6. Attack giant. Gunfire from the ship you captured should kill it for you. (The first time I tried, the gunfire didn't happen, and I died. Maybe try moving around if the bombardment doesn't happen.)
7. 
   
8. Move into the underground temple. You will find a room with three casters and an elemental. The elemental is rotating and spraying water. To advance beyond this room, you must kill the three casters. The elemental dies after the third caster.
9. 
   
10. The ceiling will now start falling on you. Avoid falling rocks, and either sneak past or kill the two guards in the next room. (I killed them, but I assume you can sneak past them).
11. 
    
12. In the final chamber, confront and kill Eliza, then take the Dreadblades.
13. 
    
14. Escape the temple, avoiding the falling rocks.
15. 
    

I hope this was helpful. Good luck!

When I was "done" with this quest I saw a quest-mark to the North and thought "Oh, maybe that's an extra quest? I'll go pick it up"...

Do NOT!

You will have to start the quest over and fight the mobs again due to phasing out.

When you kill the last Boss (again) and it says you can't equip the weapons (because you have them already - and you can't throw the already-equipped weapons out nor abandon the quest) and there's no flying for you outside - do not panic.

Use your Hearthstone to Dalaran and the quest will be completed!

-from a fellow (and a little too curious) rogue.

Video Guide: https://www.youtube.com/watch?v=xu6QbFlgJGE

1. The Dreadblades (Scenario)
• Accept the quest, The Dreadblades, from [npc=102120] at coords 40.7, 69.0 (Aboard the Crimson Veil ship docked at Booty Bay).
• Speak with [npc=102120], when you are ready to set sail for [zone=8000].

Stage 1 - Maritime Diplomacy
• After arriving in Dead Man's Bay, activate/maintain your Stealth, and travel northeast toward 60.6, 68.6.
• Watch out for the [npc=102191] mobs, as they can see through your Stealth.
• Board the Horizon's Edge ship, and fight [npc=102185] until he retreats at about 25% health.
- - Avoid standing in the red dashed-lined circles where he places bombs.

Stage 2 - Blood and Plunder
• Activate your Stealth and disembark the ship, heading north to 59, 65.
- - Avoid coming into contact with the traps on the ground.
• Continue up the path to 56.7, 66.4.
- - Steer clear of the [npc=102192] as they have a heightened Stealth detection.

Stage 3 - Eliza's Gambit
• Defeat [npc=102239] after [npc=102249] finishes speaking.
- - When you hear [npc=102212] launch a cannon strike, kite [npc=102239], into its blast radius, as it will be stunned and take increased damage with [spell=201860].

Stage 4 - Into the Depths
• After defeating [npc=102239], proceed southwest to the temple door at coords 56.0, 68.7, and pick the door lock by clicking on the door.
• Enter the chamber below where a [npc=102300] will come up from the pool of water, casting an ability similar to [npc=71543] cast of [spell=143309].
• Follow the Swirl clockwise, around the room and kill the [npc=102298] without being struck by the Swirl.
- - Interrupt [spell=208094] using Kick.
• After killing the third, and final, [npc=102298], the [npc=102300] will despawn.
• Travel to the next room, whose passage is located at coords 55.4, 70.9.
• Stealth around the pair of [npc=102305], and continue downstairs to 54.0, 71.5

Stage 5 - Claiming the Prize (Final Stage)
• Defeat [npc=102293].
- - When she begins her cast of [spell=208226], run behind one of the columns to hide.
- - Activate your defensive cool downs when [npc=102293] casts [spell=208245].
• Click on [object=254087], from the ground, to claim your artifact weapon.
• Exit the temple, and click on the [npc=102352] located at coords 56.2, 67.9.
• The [npc=102352], will fly you back to [zone=7502].
• After landing at [zone=7502], travel back to your Order Hall.
- - One of the entrances is located in the Glorious Goods store at 52, 70. Enter the store and show your insignia to [npc=97004].
• Enter the Hidden Corridor and follow it downstairs. Follow the subsequent tunnel to the [zone=8012].
• Turn in the quest to [npc=94159].