- Fly back to Castle Exdeath. Now the barrier ‘round the Castle is gone, allowing you entrance. The first door to the north, now unlocked, leads to the second floor; check to the south to find a Diamond Shield and an Ether in the southeast and southwest corners.
- 3F. To the west is what looks like a dead end, but when you try to leave a cut scene will trigger that’ll unlock the path forward. Also, a, uh, slight shift in the decor. Ew.
- 4F. On the east side of this area there’s a switch that will get you through to an Ice Shield. Head south and west to find stairs. You can walk through the wall to the right of the stairs if you want to skip a short section.
- 5F. There are two secret pathways here, one to the right of the entrance, the other to the far north, beside the chest on your right. The chest contains an Ether. (And yes, that thing beside the chest is a door.)
- 6F. This area’s full of lava, forcing you along a narrow path. Right beside the beginning of the lava path there’s an easily-missed set of stairs into the lava; you can use it to reach a Hayate Bow. There’s another set further on, but you’ll take damage walking on the lava, so take the shorter route. (Or use Float. You’ll avoid damage entirely that way.) Just north of the exit is an Elixir.
- 7F. There’s a switch dead ahead that will activate a moving platform, and you’re responsible for stopping it. If you stop it while it’s facing a wall you’ll be forced into a battle. The left chest here contains an Icebrand; the right contains a Kotetsu. Through the middle door is a save point.
- 8F. The pathway to the north splits. Go right and you’ll find a hidden pathway at the end of the nearest dead end; inside is an Elixir. To the west is the exit, and to the far west is a chest containing 9,900 gil.
- 9F. More lava; Float it up. Head all the way east to find stairs to the next floor. At the top you’ll find 8,000 gil. Then backtrack, return to the middle of the room, and take the nearest stairs.
- 10F. There’s a series of skulls to the east, and as soon as you step on the closest one the pathway will be blocked to you. Walking on the wrong skulls will drop you back to 9F. To leave, just walk along the bottom-left skulls; the south-most skull will recreate the path and take you to a save point. On the far side of the skulls is a Twin Lance; to reach it, step on the upper skulls adjacent to each other on both sides of the platform. From here you can walk along the upper-right skulls to the northern-most skull tile, which will warp you to an optional boss battle.
Ack, irritating. Carbuncle begins this battle with Reflect already cast, and will continue to use Reflect to bounce spells at you. While Reflect is active Carbuncle will have ridiculous defences, making it almost invulnerable to physical attacks, including a lot of special abilities. Occasionally, however, Reflect will just go down, at which point Carbuncle is vulnerable to everything, per usual.
You can’t exactly tell when Reflect is going to fade, unfortunately, so you just have to keep attacking until your hits start to stick. (Carbuncle sometimes casts Cura on itself as a sign that Reflect is gone, but not always.) You can also cast Reflect on your own guys and bounce spells off of them, though this will make healing more difficult unless you have lots of items. You’ll receive Carbuncle as a summon when you best the boss.
It’s important to note that there’s no coming back to this dungeon once it’s complete, so if you want this summon you need to fight it now, not later.
- 11F. Dead ahead is an empty chest. On your right are stairs leading to a small room that contains a Partisan and a Fuma Shuriken. Try to go through the northern stairs, though, and you’ll get into a rumble. (Though this only happens if you opened the empty chest in the middle of the room.)
Persistent. This is your final actual battle with Gilgamesh, and it’s a teensy bit easier than before. Still a reasonable damage-dealer, Gilgamesh now tries to harry your party with a slew of status ailments, the most persistent and annoying of which is probably frog status. All suck, but if you have Esuna it’s easily healed. Beyond that you just need to beat on him until he changes into his ‘true form’. At this point he’s pathetically weak, and the battle will end automatically after a few rounds. Note that in this second form you can Steal the Genji Helm from Gilgamesh, an excellent piece of equipment. When Gilgamesh goes down you’ll receive the Excalipoor, a truly pathetic sword.
I highly suggest returning to the save point and healing if you fought Gilgamesh, because you’re about to face someone slightly more intimidating on the next level.
This battle isn’t as brutal as you might have expected, but it’s bad enough. Exdeath is your semi-standard black mage type, and he likes using -ga level spells to inflict in the 800s worth of damage. He also enjoys gravity-based magic, and can both gradually sap your health and just flat out do a ton of damage with them, though not that often. Once his health is depleted to an extent Exdeath will start using two moves in a single round, which can swiftly kill a character. He’ll also rarely force your characters to swap their rows, though this is a minor, temporary nuisance.
Nevertheless, this battle isn’t horrifying as long as you have a few mages on hand. Shell can offset the damage from Exdeath’s magic, Haste will get you some extra attacks, and, if you have a Blue Mage ready, Level 2 Old will sap his stats and expose him to more damage in general. If you have a Chemist for healing you can also set up Reflect on your characters and demolish Exdeath with his own spells. Barring that, the Aegis Shield you (hopefully) picked up in the Great Forest of Moore can nullify half of his Firaga and Blizzaga combos. You can also use Holy on Exdeath (obtained by killing Metamorphs in Ghido’s Cave) to take advantage of his weakness to holy magic. All this aside, strong attacks in general - Focus, Throw, Jump, Zeninage - will all help take him down for the count.
Once Exdeath is dead you’ll watch a cut scene, and, confusingly, you’ll wind up near Castle Tycoon. What’s more, if you open the World Map you’ll discover that it now looks quite different. More… robust, maybe? Uhhh…