In Narshe in the world of ruin, get Locke first and then you will be able to open the doors because Locke is a thief.
When Kefka is in Narshe and he is trying to steal the esper (Tritoch). After you kill all the others there is one acting as a "bodyguard" for Kefka to Skip a battle with him just equip some Sprint shoes him/her, hold O and just jet past him to kefka you may be thinking that is stupid I could be getting more exp. But you could be saving a much needed potion, tonic, or Tinticure. Just think about it.
To do this you must be in the World of Ruin (After the World is destroyed by that Lunatic Kefka. Well it was Shadow's fault also but he's cool). When you find Locke (in the Phoenix Cave) Go to Narshe with Locke in your party and go to the weapon shop and he should unlock it for you and you will find an old man in the shop. He will ask you if you want an esper or a sword. The sword does a critical hit of 9999 (well close to it)each time. The esper has Ultima spell it does around 4000+. Pesonaly I think the sword and the spell are cool. To bad you can't have them both.
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