Final Fantasy IV/Toroia and the Dark Elf

Locate Toroia
To the northwest of Baron is the town of Toroia, where Kain told you the Earth Crystal is located. There is a small piece of land to the right of the castle, above the town where you can land the airship. Land there, and enter the castle.

Speak to Edward
Go straight ahead, until you reach a room with the 8 women. Speak to them and they will tell you that the Dark Elf stole their crystal. Now leave that room, and go through the door on the left side of the next room. Eventually you will find Edward lying in bed. Speak with him and he will give you the TwinHarp, an item you will need in the Dark Elf's cave.

Black Chocobos
Leave the castle and go north. When you see a clearing with a small clump of trees, walk into the middle of it. Find a black chocobo and speak to it. It will allow you to fly across the river to the east, so that you can reach the cave where the Dark Elf is. Enter the cave.

Magnetic Field
When you enter the cave you find out that there is a magnetic field that makes it impossible to use metallic objects. You need to equip Leather or Cloth armor, and a bow for Cecil.

Magnes Cave
When you first enter the cave there will be bridge to the east. Once on the bridge take the path to the south. Follow that path until you reach the staircase. Go down to the next level. In the next room go across the bridge, and to the left. Go down that staircase to reach the next level.

Lower Cave
In the next room, there is a save point through the first door found in that room. After saving, continue on across the bridge to the south, and then across the bridge to the west. Go through the opening in the cave wall on that island, and finally through the door. In the next room go to the next staircase immediately on the left.

B4F
In this final room go to the left, and there are a series of torches leading up to a door. Go through that door and you will reach the Dark Elf. Once in that room, speak to the Dark Elf and he will engage you in battle. You wont be able to fight him at this point and you will be killed. At this point the TwinHarp will play and you will be able to re-equip metallic objects and you will be able to really fight the Dark Elf.

Dark Elf
When you attack the Dark Elf again, he will not be able to do as much damage as before Edward aided you. Attack it for a little while and it will turn into a dragon. This fight is very simple due to the effectiveness of the spell Weak. Have Tellah cast this spell, and the dragon will be down to only a few HP. One more attack and it will be dead. Now take the Crystal and leave the cave. Get in the Chocobo and it will take you back to the Chocobo forest. Walk back to Toroia Castle.

Kain Takes the Crystal
Go back to the room with the 8 Clerics. You will hear Kain's voice and the clerics will allow you to keep the crystal. Go outside and get into the airship. Kain will fly in with his airship and you will be taken to the Tower where Golbez and Rosa are.