There are a total of seven Seven-Star Swords, each of which must be upgraded three times. To upgrade one, simply combine it with a higher-level sword. If the weapon you choose to combine it with isn't high-enough level, Toady will tell you it's not going to work well. You can tell when a sword is done because its name will change. For example, Desert Seeker -> Desert Seeker II -> Desert Seeker III -> Earth Shaker. Earth Shaker is the final form.
As you move through the game, watch for people with blue bubbles over their heads; they will have clues to the swords that will be recorded in your Info Edge. Most of the info below came from my Info Edge.
The Seven Swords:1. Desert Claw will give you the
Desert Seeker at the very beginning of the game.
2. Speak to the guy in the Item Shop Corbis in Vedan. Buy The Annals of Hades when you can (Platinum Hunting License required).
Give the book to Rodullier in the shop, and he'll read an excerpt:
1. The treasure lies in the ancient ruins of the Sylvazard Desert.
2. The password is: "It's not Shisa; it's Caesar!"
Head to the Tablet Pit on Rosa and speak to an Elderly Man. He'll ask for the password. Tell him Caesar, and he will give you the sword
Great Caesar.
*Story Spoilers*
3, At a certain point in the game, a new chest will appear in the church at Rosa. It will contain
The Pride of Kings. You must have the Star Key to open it.
4. Speak to Nico in the Cancer King ruins of Vedan. he will tell you that Cosmolore is being held by Chrisden Ark.
Speak to Mesod in the Ruins leading to the Leo King on Juraika. He will tell you the sword is being held by an infamous space pirate.
Speak to Silma in the Gladius Towers of Zerard. He will tell you that Chrisden Ark was friends with Dorgen-something-or-other.
Speak to Carraco in the Control Room of the Dorgenark. He'll tell you the ship was built by Dorgengoa and Chrisden Ark. There's info about it written on a monument in the ship somewhere.
Read the plaque in the room behind the Control Room to receive the
Cosmolore.5. At the Rosa spaceport, speak to Agassimo to be told about the woman at the church who can hear swords talking.
Speak to Misanna in the church to get factory blueprints for
Ixion.6. At the entrance to the labyrinth in the Sylvazard Desert on Rosa, speak to Kyralil Bell. She'll tell you she's worred about her friend Blaster J. who is somewhere in the labyrinth.
Search the labyrinth until you find Blaster J. (he was in the very last room for me). He will give you the sword
Pegasus Lord.7.
Duke Nightmare is the only sword that has no clues in the Info Edge (at least none that I found). I had to look this one up.
You create Duke Nightmare by combining other swords.
Alexander + Plain Edge = Alex Impulse
Alex Impulse + Spirit Calibur = Demon Rouser
Gustbringer + Adamon Raiser = Majestic Halo
Majestic Halo + Demon Rouser = Duke Nightmare
Locations:
Alexander - Rant, Zerard
Plain Edge and Gustbringer - Mohandis, Rosa
Spirit Calibur - Kayo, Vedan
Adamon Raiser -Narcissus, Mariglenn
Thanks to
http://www.cheatsguru.com/ps2/rogue_galaxy/walkthrough/....htm for the Duke Nightmare info.
So, your seven swords will be (first and last iterations):
Desert Seeker ->> Earth Shaker
Great Caesar ->> Babylon Reborn
Pride of Kings ->> Kingdom Master
Cosmolore ->>Ragnarok
Ixion ->> Guard Axis
Pegasus Lord ->> Gryphon Lord
Duke Nightmare ->> Dark Cloud