Gaikoz's Castle is the twelfth dungeon encountered in-game, and the last dungeon on the Bermesiah continent. Players commonly come to this dungeon to obtain Ronan using the Worn-Out Ronan Mission.
Ronan, hired by Kanavan to defeat a ghostly samurai here, requested the Chase to come here to support him to eliminate Gaikoz.
They do so, while noting that Gaikoz was once a warrior who lost his lover during the war(possibly the one between Serdin and Kanavan) and then died somehow. Kaze'aze ressurected him, and he wants vengeance because of his lost beloved.
When the Ghost Knight himself is confronted, he mocks the Chase saying that "Kaze'aze is building a bright future", which is a lie.
Gaikoz himself is defeated, and Ronan thanks them for their support. He joins them afterward to aid them and dispose Kaze'aze.
Elesis: So this is Gaikoz's Castle, home of the ghost knight. Lire: He lost his lady love in the war, and then lost his own life when he fell into a trap. Elesis: Then all that resentment's what's turned him into the specter that he is. Arme: I can’t help but feel a bit sorry for him... Elesis: In any case, we seem to have walked into a monster's paradise. But first, let's go to where Gaikoz is...
Boss[]
Elesis: Gaikoz! Gaikoz: Grand Chase, why do you resist what could be a bright future? Elesis: What bright future?! Lire: Isn’t this "bright future" you speak of filled with pain and suffering for all? Gaikoz: Creating a bright future calls for great sacrifices. Lady Kaze'aze taught me that. Lire: If that's the case, then we'd rather choose the past. Gaikoz: Choose the past? Fine, then I shall send you into eternity along with your precious past! Arme: Gaikoz. Your body has been built out of hatred for humans, and this hatred will infect your soul. Please stop... Gaikoz: Stop! I have nothing more left to lose. Fight me!
Post Boss Battle[]
Ronan: I was having a hard time fighting alone, but thanks to all your help, I was able to stop Gaikoz. Thank you. Elesis: We only did what we had to be done. Ronan, what are you going to do now? We're going after Kaze'aze. Ronan: I see. I would like to join you on your mission and dispose of Kaze'aze. Arme: That's great! For peace in Serdin and Kanavan! Lire: Now we have another member. This is so encouraging. Ryan: It's so reassuring to have the head of the Kanavan Royal Guard with us! Ronan: I look forward to fighting alongside you. Elesis: Me, too! Arme: Me three!
Trivia[]
Although Ronan is stated to appear here, he only appears in Dialogue, not in action.
Gaikoz's Castle is very similar to Himeji Castle in Japan.
This is one of the Dungeons which was rebooted after the release of Dio.
In Season 3, there was a glitch where Gaikoz was level 22 rather than 24. This glitch has been patched.