Instructions
Travel to the town of Lohan and then head southeast to Hellena Prison. Make your way through the prison to be automatically returned to the town of Seles. One of the characters here informs you that Emperor Doel is residing at the Black Castle of Kazas.
Exit the town and head southwest on the world map to reach the castle. Upon entering, your party will find itself in the town of Kazas. The castle entrance is down and to the left of where you entered the town.
Talk to the boy blocking your entrance until he lets you pass. Speak to him again when you are ready to enter the castle and he will show you the passage. If your characters are not at least level 13, it is recommended you level them up first for a better chance at survival.
Go down the ladder and enter the castle. Go past the knights standing in front of a elevator and speak to the researcher at the right of this area to receive special oil. This oil allows you to activate the elevators found in the castle.
Continue exploring the castle until you have found a red, yellow and blue stone. The red stone is in the area with the falling debris; the yellow stone is a gift from the commander in the area with the fighting knights; and the blue stone is in a treasure chest.
Take an elevator to the fourth floor of the castle and put the three stones in the slots in front of the statue. Go through the door this opens and use the elevator to reach a character named Kongol, who you have already faced in the game. Defeat him in battle and take the stairs. You will find Emperor Doel -- the final boss for the first disc of the game.