Sail to the island in the northeast of the world map with a small lake in the middle. There you'll find the Castle Deist
Talk to the child twice, both times he'll just run away.
Take the stairs (A) to 2F.
- C-53: Cottage - Top-left corner chest.
Take the exit (B) in the top-right corner back to 1F.
Head west and enter room (C) with 8 chests:
- C-54: Eye Drops - Top row, 1st chest.
- `C-55: Antidote - Top row, 2st chest.
- `C-56: Cross - Top row, 3st chest.
- C-57: Mallet - Top row, 4th chest.
- C-58: Gold Needle - Bottom row, 1st chest.
- C-59: Sage's Wisdom - Bottom row, 2nd chest.
- C-60: Saint's Spirit - Bottom row, 3rd chest.
- C-61: Wing Sword - Bottom row, 4th chest.
Head south, then enter the second room (D).
- C-62: Stop Tome - Left chest.
- C-63: Stun Tome - Middle chest.
- C-64: Curse Tome - Right chest.
Leave the room, continue heading south.
- C-65: Unicorn Horn - Chest to the south from the room (D).
Backtrack to 2F, then use the exit (E) in the bottom-left corner to 1F.
- C-66: Phoenix Down
Head back to 2F, then talk to the lady and the child to learn more about the Wyverns and the pendant. This is optional, though.
Exit the castle, head north to the cavern.
Deist Cavern
This cave is located in the south of Castle Deist. Our first objective is to find a pendant and come back to see the Wyvern.
- C-067: 230 gil - From the entrance to our right.
This floor has 3 exits leading to different areas of B2. Take the top-right exit (A) first.
This will lead you right to the pendant.
- Key Item: Pendant - Pick it up from the Dragoon's helmet.
Exit the cave and go back to the Castle Deist.
Proceed to 2F and talk to the Wyvern in the room, then select "Ask -> Wyvern".
The Wyvern will ask you to bring the egg to the Hot Spring deep within the Deist Cavern.