Muramasa?

what is this sword? what does it do never saw it or heard of it on my PS1 version of FFT please help.

[T.G. Oskar]

Are you sure you haven't seen the Muramasa? Or are you referring to the Masamune?

Muramasa can be bought on stores after the 4th chapter, and it's one of the last katanas that can be bought (alongside the Kikuichimoji). After that, there's the Masamune and the Chirijiraden. When used for "Draw Out", it does an area attack with red spirits.

If you are referring to the Masamune, check Elmdor's equipment when facing him in Limberry Castle (don't worry, that isn't much of a spoiler). He'll have it equipped.

[Mistress Sheena]

That, and ninjas will throw that sword and the Chirijiraden at certain levels in the Deep Dungeon.