Rogue Galaxy
35 Achievements
80-100h
Space Whiz
Receive the Key to the Underworld by completing the Seventh Mystery. Details for this achievement will be revealed once unlocked
3.8%
How to unlock the Space Whiz achievement in Rogue Galaxy - Definitive Guide
The earliest chapter you can obtain this trophy: Post-Game Only
After finishing the game and saving, you'll notice that your save file is now marked with a silver star. This means that you now have the post-game optional dungeon available to you. Load up your save file with the silver star and return back to the Dorgenark; now attempt to go to another planet and a new destination will be made available called the Ghost Ship. The Ghost Ship is an optional quest that will enable you to fight bosses you fought before from previous chapters (Mud Whopper, Individer, Logan, Gyzel, Beast Leone). On this ship you'll be fighting a Young Man (Dorgengoa) and the ship's owner, Arabis. Arbais' is the final boss fight at the end of the Ghost Ship. Both Dorgengoa and Arabis have been corrupted from Doppelganger who is the final boss of Ghost Ship Extreme. Once you've defeated Arabis and conquered the Ghost Ship, you'll receive Jaster's best outfit and sword: Captain’s Uniform and Dorgenedge.
Once you've completed the Ghost Ship, there will be a new NPC named Minoc who's located to the right of the nearby Transporter Entrance save point. If you talk to him, he'll challenge you with a seven question trivia game. These seven questions are all game-related and they're all random. These questions are all multiple choices and he has a list of about 70 questions. Additionally, you won't know if the answer you've selected is correct or not until you’ve finished answering all seven questions, but even then the NPC won't tell you which questions were right or wrong.
Thankfully, all these questions/answers can be found from GameFAQs all over the internet. For a list of all The Seventh Mystery questions/answers, consult Double G’s 7th Mystery Answers Guide (CTRL + F is your friend, use it to find a keyword or words on a page).
After answering all seven of Minoc's Seventh Mystery questions correctly, he'll give you the Key to the Underworld and leave behind a Thinking Circle, thus unlocking the trophy.