Originally Posted by
Flying Mullet
The Coliseum requires a little bit of luck and a lot of planning ahead. Since you can't control your characters in the coliseum you always want to save before every bet. That way if the battle doesn't go your way you can reset and you don't lose anything. As to your situation, see what attacks the Rhyos does, then equip accordingly. If it does a thunder attack, equip the Thunder Shield. If it poisons and confuses, equip the Ribbon, etc... In general I find that the Ribbon is always a good relic to have equipped at the Coliseum. And since Terra can equip the most powerful weapons in the game, try putting a Genji Glove and/or Offering on her so she'll do some good damage when she attacks. Having learned Ultima can't hurt either, but I find they rarely cast the good spells.