With the Airship, you can reach anywhere in the world. Before hunting the next Fiend, take a detour to unlock your party's advanced classes. The Citadel of Trials holds the Rat's Tail - the key to meeting Bahamut.
Getting to the Citadel
The Citadel of Trials is in the northern central area of the world map. Fly there with the Airship and land on the western tip north of the citadel. Walk around the coast and head southwest. You'll need to cross a river with the Canoe, then continue south to reach the entrance.

Citadel of Trials

Inside, talk to the man in the center and show him the Crown (from Marsh Cave). The throne in the northwest room now teleports you to the rest of the citadel. This dungeon relies on portals to navigate - step on the wrong one and you'll loop back. Check the bestiary for enemy weaknesses.
Portal Maze
From the throne room, take the first portal. In the next small room, use the only portal. When you reach a room with two portals on the left side, take the lower one. Go around the short wall to the next portal. In the room with two portals on the right side, use the bottom-right corner portal.
Walk through the hall to the portal at the south end. In the room where you start in the southeast corner (two portals), take the right-side portal closest to you. Walk east through either path and enter the room for a Potion. Head south through the left hall and take the center portal in the open area.
Treasure Floor
Take the stairs to the third floor. No more portals here - just treasure and enemies. Walk north through the hall to the first room. You'll fight 2 Nightmares to get the Healing Staff - it casts Heal when used as an item.
Head to the northwest corner for a Ruby Armlet, Ice Brand, and Steel Gloves. Go south to another room with more chests including Gauntlets (casts Thundara when used). Finally, head east to the throne room where the Rat's Tail waits.
Dragon Zombies
Two Dragon Zombies guard the chest with the Rat's Tail. Talk to them to start the fight.

After the fight, grab the Rat's Tail from the chest. Sit on the throne to teleport back to the first floor, then leave the citadel.
Bahamut and the Cardia Islands
Fly southwest to the Cardia Islands - a group of five islands in the sea. The caves on these islands have treasure worth grabbing: Dry Ether, Elixir, X-Potion, and plenty of Gil. Explore all of them except the tiny island with just one dragon.
On the island with two caves, enter the eastern one. Travel through the tunnels and two floors until you reach a room with stone crosses. This is Bahamut's chamber, King of Dragons.

Show Bahamut the Rat's Tail. He recognizes your courage and grants your entire party the class upgrade.
Class Changes

This is one of the biggest power spikes in the game. Each class transforms into an advanced form with new abilities:
- Warrior → Knight - Can use White Magic up to Level 3 and equip the best gear in the game.
- Thief → Ninja - Can use Black Magic up to Level 4 and equip almost any weapon and armor.
- Monk → Master - Gains new equipment options. Still deals high unarmed damage.
- Red Mage → Red Wizard - Access to magic up to Level 7 in both schools.
- White Mage → White Wizard - Can learn Level 7 and 8 White Magic including Full-Life and Holy.
- Black Mage → Black Wizard - Can learn Level 7 and 8 Black Magic including Flare.
Your Knight and Ninja can now learn spells. Buy Cure and Protect for your Knight from Cornelia, and Fire/Thunder for your Ninja. Check Elfheim and Crescent Lake for any spells you skipped. With your upgraded classes, you're ready to hunt the Fiend of Water. Fly to Onrac on the eastern continent to begin the search for the Sunken Shrine.
Treasure Chests
Two locations have treasure in this chapter:
- Citadel of Trials - Healing Staff, Ruby Armlet, Ice Brand, Gauntlets, and more
- Dragon Caves - Dry Ether, Elixir, X-Potion, and Gil