Here is a section devoted to that ever important guy.

To meet him you must be on the second or third disc. Go to the house on the left side of Kalm then go upstairs. He's standing right there.

If you decided to talk to him he'll tell you the following things. That he is going on a journey for his lost friends. He also needs the following things a Guidebook, a Desert Rose, and a Earth Harp. This is your chance to help the guy out and get some great stuff in return.

To obtain the Guidebook you must go to the passage way in the underwater reactor in Junon. Here you will fight a ceature called a Ghost Ship. All you have to do is morph the Ghost Ship to collect your prize. Upon giving it to the Kalm Traveler he'll give you the Underwater materia.

With the Underwater materia you can now go fight Emerald weapon without the time limit. Once you defeat Emmy( see my Weapons strategy section) you will get the Earth Harp. Once you cash this in you'll recieve the THREE MASTER MATERIA. SWEET!!!!

All you have to do now is defeat Ruby weapon( again see my strategy guide). Your prize for defeating Ruby is the Desert Rose. Now go give the Kalm traveller the final item. In return you'll get a Gold Chocobo. This is a pretty crappy gift considering you probably already have KotR. Also the bird has crappy stats so racing it isn't really an option.