It's the falls where you picked up Magic Lamp. Accessible via the Cave on the ocean floor.
Bestiary Checklist:
Alchymia always shows up with a frog with an unknown name (???). If you attack the frog first, it'll transform the frog into a random monster. Fun fact: if you use Maiden's Kiss on the frog, it'll transform immediately.
Follow the map below because the water streams will prevent you from going back to previous sections.
On B2, the switch can only turn off the water stream (a) for a short time, so quickly open the chest for Protect Ring.
Item Checklist:
- C-184: Ether
- C-185: Turtle Shell
- C-186: Air Knife
- C-187: Goliath Tonic
- C-188: Rune Blade
- C-189: Protect Ring
Steel Fist starts showing up here. It will counter any physical attacks, so it's better to kill them with magic.
On B4, there are 2 pits you need to avoid; see the map below.
On B5, make sure you collect all chests before stepping on the pits #8.
Item Checklist:
- C-190: Phoenix Down
- C-191: Reflect Ring
- C-192: Artemis's Bow
- C-193: 12000 gil
- C-194: Enhancer
- C-195: Fuma Shuriken
- C-196: Aegis Shield
- C-197: Titan's Axe
Make a Quicksave before fighting the boss.
Boss: Leviathan
Steal: Elixir
Guaranteed Drop: Reflect Ring
Leviathan is weak against thunder. So, the easiest strategy is to go full Black Mages equipped with Thunder Rod and Magnus Rod and quickly spam Thundaga. He should be down in 2 turns. A safer strategy, especially if you are low level, is to equip Coral Ring on everyone to absorb his deadly attack Tidal Wave. You should have 3 Coral Ring from when I asked you to buy them in Phantom Village.
Backtrack to your Submarine.
Legendary Weapons
Go to Kuza Castle to collect the last 3 legendary weapons. See 50. Legendary Weapons for more info.