Once you touch the crystal in the Lunar Whale, you'll be forced to go inside Giant of Babil which is another one-time visit dungeon.

Make sure to farm all Bestiary. Here is a checklist:

• Clockwork Soldier
• Beam Cannon
• Clockwork Dragon
• Armor Construct
• Searcher
• Centaurion

There is a save point and a Sundries in room #4, I suggest you buy more Shuriken for Edge, you'll need it for the next bosses.

When you go in room #5, you'll be fighting the 4 elemental fiends that previously fought before, but this time you'll be fighting them consecutively.

Bosses: Scarmiglione, Cagnazzo, Barbariccia, Rubycante
Strategy: 

• Scarmiglione: he is weak against Fire and Cure spells.
• Cagnazzo: watch out for his Tsunami attack, when you see water surrounding him, immediately use any thunder-based magic. He is also weak against Ice.
• Barbariccia: she is tough and Kain is not in your party, so the best way to beat her is having everyone attack. When she is in Tornado mode, Cecil, Edge and Rosa switch to defense mode, while Rydia summon any Leviathan or Bahamut and Fusoya uses Black magic.
• Rubicate: not so hard as long as you have Edge uses Steal when he opens his cloak.

I suggest you head back and save your game, then unequip Fusoya before entering the next room.

Boss: CPU
Strategy: it has 2 nodes Attack and Defend. If you kill both nodes, it'll regenerate both of them so the plan is to just kill one (I highly suggest you kill the Attack node), then focus on the CPU, finally the Defend node.

Item checklist:

• Fuma Shuriken
• Hi-Potion
• Ether
• Yoichi Arrows
• Siren
• Soma Drop
• Silver Apple
• Elixir