Getting Odin Esper
Use the following trick to get the Odin Esper quickly, without getting into battles. After receiving the Airship in the World Of Ruins, go to Narshe. Go to where the Moogle Village is located. Talk to Mog and he will join the party. In the location where you found Mog, search the wall to retrieve the Moogle Charm (when equipped on Mog, you will fight no random encounters). Go to Figaro Castle and talk to the engineer to head back to the desert. When the castle is moving, you will suddenly stop and the engineer will mention something. Go to the prison cell with the door and go through. Have Mog in the party with the relic Moogle Charm equipped. Follow the path until you reach the Ancient Castle. Go to the throne room and search the statue to retrieve the Odin Esper. You will never encounter an enemy unless you open two chests that contain monsters. If this happens, just cast Vanish then Doom to dispose of them. This is an easy way to get Odin and learn the rare spell Meteor.