Final Fantasy V/Gorn Town

With the Black Choboco, you can head to Lix, Butz's home towm, or return to Cid to continue the main quest. Cid will report they found King Tycoon, who was entering the Quicksand Desert.

Quicksand desert
When you first enter the quicksand desert, you can only get as far as the entrance when the sand pushes you back. If you already spoke to Cid about King Tycoon, he will help attract the sand worm, who will bridge the entrance.

Unlike what Mid gives as advice, the Sandworm can be attacked with Physical attacks or magical (but if you choose magic, retreat after killing it and use a tent.) It only uses a weak attack, but it constantly jumps from hole to hole, and attacking an empty hole will cause a counter attack that halves the health of a target.

Ruined City
There's no monsters in this section, giving some breather time from the difficult quicksand desert.

Approach the stairs in front - when you do, you will spot King Tycoon. He will flee to the east. Give chase, and he will head to the north. To catch up with him, head to the center building just past the stairs. When you approach, a trap door will bring you to an underground area.

After landing, continue left and go through the door. The platform will make a one-way teleport to an underground area beneath Cresent island. When you exit the destination and climb the stairs, head to the south and push the lever at the bottom of the room. This will send you on a short scavenger hunt, where you need to check the plants in the center room, the paper on the right, and the pot in the left room. After reading the book, you can retrieve two Shurkiens and the Size spell.

Return to the stairs, and head north by pushing the lever. Continue along past the Steamship (which you can visit if you want), and to the Airship. It will launch once you speak with Cid inside the ship itself. After it launches, speaking with Cid will alert you to the ship being pulled down: Crayclaw will attack.

Crayclaw is a Level 48 boss with 2000 HP. It first attacks with Tailscrew, which reduces a target a critial HP amount. Tailscrew will fail if the players are between 1-9hp. However, it is vulnerable to thunder, and should not take more than three hits from Bolt2. When it is defeated, the skys are now yours for good.