Quote Originally Posted by Jiro View Post
An "instrument of attack" is a weapon of some description. If it can be found in the inventory, then it may be some kind of item that causes damage a la the Flare stone, or it might be one of the items that you can use to learn blue magic and/or upgrade GF affinity.

I actually think it's the item that teaches Quistis Degenerator.
could it possibly be a weapon component?