At this point, you cannot open your world map nor counter any random enemies yet until the end of this section.
Castle Tycoon
Last chance, will be inaccessible after this.
Enter the castle and head straight to the throne room.
After the cutscene, leave the throne room via a south door to the balcony and talk to Krile.
Leave the castle.
Boko
Make your way to the Pirate's Hideout (follow the map direction below).
Note that you can ride Boko to cross rivers.
Death Valley
Follow the map direction below to the Death Valley. It's located west just after Tule village.
Make sure you save before entering the valley.
If you have Water Scroll in your inventory, then change both allies to Ninjas; otherwise, change to Black Mages.
Boss: Antlion
Guaranteed Drop: Cottage
The easiest strategy is to start the battle with Sleep, then spam magic spells until you win.
Notable skills/spells: Water Scroll deals the most damage, elemental spells are great too, and Bio deals almost the same damage with less MP.
Continue south, you'll see a cave.
Ghido's Cave
Enter the cave and head straight to visit Ghido to trigger a cutscene.
Library of the Ancients
Last chance, will be inaccessible after this.
Take the stairs to the roof, then talk to the scholar on your right to learn a new song Mana's Paean.
Leave the library.