Castle Deist's water supply was poisoned by the Palamecian Empire, slaying almost every Dragoon and Wyvern. After the destruction of the Dreadnought, Firion and his comrades come to Castle Deist seeking the Dragoons' help. Firion only finds Elina and Kain in the castle and the party discovers the Dragoons have been killed, and only one Wyvern remains. To preserve the Dragoons and Wyverns, Firion is given a Wyvern egg by the last Wyvern to take the Spring of Life in the nearby Deist Cavern. After the egg is laid, the last Wyvern dies.
After meeting Ricard Highwind, Firion and his comrades accompany him to Deist where he speaks to Elina and offers to raise her child. If Firion returns after Ricard is killed by the Emperor, Elina and Kain will leave the Dragoon castle and move on with their lives, giving the party the Excalibur, the treasured blade of the Dragoons.
|Cure Tome||First Floor|
|Eye Drops||First Floor|
|Gold Needle||First Floor|
|Sage's Wisdom||First Floor|
|Saint's Spirit||First Floor|
|Curse Tome||First Floor|
|Stun Tome||First Floor|
|Stop Tome||First Floor|
|Unicorn Horn||First Floor|
|Excalibur||Speak to Elena after events at Palamecia Castle|
All found outside.
- [37.5%] Stalactite x2-4
- [37.5%] Ogre Mage, Land Turtle x0-2, Ogre, Stalactite x0-2
- [18.8%] Ghast x1-2, Ghoul x1-2, Shadow x1-3, Wraith x1-3
- [6.2%] Hill Gigas x1-2
The background music that plays inside Castle Deist is called "Ancient Castle".