Trading five stacks of crystals, or completing Bat Hunt 9 times, will give the necessary rank points for this mission.
After accepting the mission, enter the Great Hall of Chateau d'Oraguille, and go to the king for a cutscene.
After the cutscene, talk to Rahal in the Royal Knights' Quarters to receive a temporary key item Crystal dowser.
Form a full alliance of level 65+. Level 65 is still borderline aggro to the weak mobs of Temple of Uggalepih, so they will need to carry Prism Powders due to the magic sensitive mobs in this place. A level 72+ character is safe from aggro from the weak mobs.
Take Teleport-Yhoat and make your way to the main entrance of the temple.
Once you zone, take the right path until you zone back into the jungle. Follow the way round, when you see a flight of stairs in front of you leading down go left and instantly left again and you will zone into another part of the temple (map 2). After zoning, follow the right wall until you pass by a wooden gate. Shortly after you pass this, the path will split. Take the left path and clear the area.
After the guardian is defeated, continue past that door that will now open and advance up either of the two stairs that are to the west and east sides of the room. Watch out for Manipulator who usually patrols the stairs. Use the Prelate Key to open the door and continue onto map 4. Head south and take the left path until you see 4 doors on the right. Door 1 is the furthest down, Door 4 is the first door you will see.
It is not necessary to farm the Prelate Key. Instead you can use any magic spell to aggro a mob through the Door. Once the engaged mob gets near the door, it will open. However, it may take a long time until a Hover Tank gets near enough to magic-aggro.
Clear the hallway of tonberries and magic jugs. Now enter Doors 1, 2, and 4 and inspect the ??? for a key item.
Room 1 has two ??? - be sure to get the correct one which is located on the shelves to the right when entering the room. Everyone needs 3 "Piece of a Broken Key" key items before continuing.
Once everyone is ready, have someone inspect Door 3. Once this door is inspected, 2 Doll NM will spawn, Nio-Hum and Nio-A.
The NMs have extremely high magic damage reduction.
You may spawn the NMs with Sneak active and pull only one with a ranged attack, a job ability such as Provoke or simply approach one of the dolls carefully without sneak to agro it (they will not link, similarly to the two krakens in Coming of Age). Due to the narrow hallway and location of where they spawn, ranged attack is recommended, as you may have problems sighting the mob to use the job ability. You may pull either Nio-A or Nio-Hum and wait for to the other to despawn (don't kill too quickly). Only one NM needs to be defeated.