Instructions
Examine a hunting board to get "Truth Shrouded in Mist." This mission does not appear until you have reached the rank of Riskbreaker, completed Girguvegan in the storyline and completed the hunting mark mission "Wyrm Wrath's Renewal."
Talk to Koqmihn. He is found in Old Dalan's Place, which is located in Lowtown. He gives a vague reference to the location of the Behemoth King, but does not specify where exactly he is or how to get him to appear.
Go to the Feywood.
Kill all of the enemies in the Edge of Reason and Ice Field of Clearsight. These are the two areas outside the exit to Girguvegan, on the southwest side of the Feywood.
Kill the Behemoth King. Equipping Bubble Belts and Black Masks on all of your characters decreases the amount of damage he can do, but he still poses a significant threat. Part way through the fight, he begins to use the Paling Shield and Magick Shield abilities. Paling Shield makes the Behemoth King immune to physical attacks. Scourge and Shock are the most effective spells to use on him. Magick Shield makes him immune to spells. When this shield is in place, strike him with physical attacks.
Return to Koqmihn. He tells you a riddle as to how the Rod of Faith is obtained, but only vaguely hints at where and how to get it.
Go to Mount Bur-Omisace.
Unequip Vaan's weapon so that he is unarmed.
Examine the wyrm fossil located in the middle of this area. The Wyrm Snout Plunder falls out of the fossil after Vaan strikes it.
Pick up the Wyrm Snout Plunder to get the Rod of Faith and 500,000 gil.