As soon as you accept this mission, the gate guard will send you to Heavens Tower (H-6/7 in Windurst Walls).
Go inside the Door: Clerical Chamber and talk to Kupipi who is behind the counter. She will tell you about the other two nations and hand you a key itemLetter to the consuls. You can do the 2 nations in any order.
Report back to Kasaroro in the Windurstian Consul. The San d'Oria part of the mission is complete.
Now make your way to the Windurstian Consul in Bastok Metalworks. Talk to Patt-Pott at I-7. He will direct you to speak to Pius at the Department of Industry in the President's Office. Then you will be directed to speak to Grohm who is in the Craftman's Eatery.
After the cutscenes in Bastok, you will need to form a level 25 party (highly suggested that you have a BLM or RDM for sleep) and make your way to Palborough Mines.
You will only need Sneak while in the Mines. Make your way to the third floor by taking an elevator located at I-8 (or just use the handy maps to make your way there however you like).
Everyone will need Sneak on the third floor. The party must have equipment that is legal for the BCNM fight as it is capped at level 25. The zoneline for the BCNM is located at H-10 on the third floor.
Only 6 members of the party will be allowed to enter this battlefield. When you're ready to enter, have one of the people who has the Mission active click on the Burning Circle and enter the battlefield. You will be fighting:
Note: Good strategy is to fight the Seeker first, then attack the dragon.
Go to Palborough Mines to try and mine up some Mine Gravel from the Mythril Seams that are found throughout. One is located at I-8 on the first floor on the west side of the river, another at I-9 on the third floor. Trade a Pickaxe to the Mythril Seam until you receive the Mine Gravel. Alternatively, you can actually buy the Mine Gravel from the AH.
Once you get the gravel, make your way to I-6 on the second floor. You will find a refiner with a lid and a lever. Trade the gravel to the refiner and pull the lever.
Just drop off the ledge here to the floor below to find another lever. Pull this lever and you will receive some Mythril Sand.
Now head back to Patt-Pott in Metalworks and trade the sand to him. Talk to him one more time.
You will need to form a level 25 party (highly suggested that you have a BLM or RDM for sleep) and make your way to Horlais Peak. You need to go through Ghelsba Outpost to get here. From Ghelsba Outpost you can go through either Yughott Grotto or Fort Ghelsba - follow the maps to make your way there.
You will need Sneak and Invisible while in the higher level areas.
The party must have equipment that is legal for the BCNM fight as it is capped at level 25. Only 6 members of the party will be allowed to enter this battlefield. When you're ready to enter, have one of the people who has the Mission active click on the Burning Circle and enter the battlefield. You will be fighting:
Note: Good strategy is to fight the Spotter first, then attack the dragon.
Once you've defeated the BCNM, go talk to Kasaroro again.
Now head all the way back to Heaven's Tower in Windurst Walls and talk to Kupipi to finish the Mission.
Notes
After a cutscene, cast your prefight buffs. Have the BLM or RDM to sleep the dragon while everyone attacks the Ahirman. The Ahirman must be silenced. The dragon has AOE Paralyze and a single target Petrify attack. Once the Ahirman is defeated, the dragon will go down quickly.
Game Description
Mission Orders
Determine the state of affairs in San d'Oria and Bastok, and render assistance on behalf of Heavens Tower. Inquire at our consulate in each country for more information. Traveling by ship from Mhaura to Selbina is recommended.
Mission Orders (San d'Oria -> Bastok)
Journey to San d'Oria
Go to the highest camp in the Ghelsba Outpost and defeat Warchief Vatgit.
Journey to Bastok
Something strange is afoot in the deepest levels of the Quadav-held Palborough Mines. Investigate and report. An official named Pius will give you more detailed orders.
Mission Orders (Bastok -> San d'Oria)
Journey to Bastok
Survey Bastokan mining technology, and retrieve some mythril sand from the Palborough Mines. An official named Pius will give you more detailed orders.
Journey to San d'Oria
Investigate the Yughott Grotto deep inside the Ghelsba Outpost.