From Final Fantasy Wiki

The Dwarven Castle in the DS version.

The Throne Room of the immense Dwarven Castle.

The Dwarven Castle, also known as Dwarves' Castle is a location in the game Final Fantasy IV. It is a large castle in the Underworld, where the Dwarves, led by King Giott and his daughter Luca, live. The castle contains an entire town, a Crystal, a hospital, a military base, a Fat Chocobo (known as "The Godsbird"), and the infamous "developer's room". In Final Fantasy IV, most of the passages in the castle cannot be accessed upon the player's initial entry.

Story

Final Fantasy IV

The throne room in the DS remake.

Cecil, Rosa, Kain, Yang, and Cid arrive here in order to protect the castle's Crystal, however, they arrive in the middle of a war with the Red Wings. As a result, their airship, the Enterprise, is damaged, and they have to seek shelter from Giott. Cid volunteers to repair the Enterprise for use in battle, and takes it back to Baron in order to wrap its body in Mystic Silver so it can fly more efficiently over lava without the engine overheating. After Cid leaves, Yang hears a strange noise behind the Throne in the Crystal Room, and Giott opens the door so Cecil's party can see what is going on. Inside, they encounter Luca's dolls, the Calcabrina, which are being controlled by Golbez. Cecil's party destroys the dolls, and then must face Golbez himself. Golbez paralyzes the party and summons a Shadow Dragon to attack and defeat the party. All party members but Cecil are killed instantly. However, the Mist Dragon appears at this point and defeats the Shadow Dragon. Cecil is then mysteriously healed, and Rydia, who has been missing since the Leviathan attack, appears and helps Cecil defeat Golbez. Rydia then rejoins the party. However, Golbez is able to inch along the floor and steal the Crystal.

Giott tells Cecil and his friends that the remaining Crystal is in the Sealed Cave to the south. However, Luca holds the key to the cave, and that he cannot enter it. Therefore, Cecil decides to try and steal back the other Crystals at the Tower of Babil. At this point, the entire castle opens up to Cecil.

Cecil returns from the Tower of Bab-il unsuccessful, and Giott tells Luca to give him her necklace, which doubles as the key to the Sealed Cave. At this point, Cecil and his friends command the Falcon, a former Red Wing airship hijacked by Edge. It cannot fly over the lava. Cecil finds Cid, who was injured after a failed suicide attempt, in the hospital. Cid decides to wrap the Falcon in Mystic Silver so Cecil can fly over the lava. However, Cid is injured again in the effort.

After Cecil fails to protect the last Crystal, he and his party return to the Castle, where Giott tells them of the Lunar Whale, a legendary airship capable of reaching the Red Moon, which is found in Mysidia. Cid appears and attaches a drill to the head of the Falcon so Cecil can reach Mysidia.

In the ending, Giott and Luca order the dwarves to scrap their tanks.

Final Fantasy IV: The After Years