Where do you begin with finding the legendary glass shard.
This item is extremely easy to find in much of the map, it is found in almost every house in Prehevil, you can usually find it on the floor in a pile.

Glass Shards are a consumable item that if used on an enemy's head will have a 70% chance of blinding the opponent, which means that the hit rate of the opponent will be -75% than normal.

To know if you have successfully blinded the opponent, this icon will appear

There are certain risks with using glass shards on enemies, for example,

Being hit directly after using them

Being unlucky and being hit through blindness

And straight up just missing the glass shards.

During my own Termina playthough I used glass shards only a couple of times

One Enemy that I used it on when they were causing me trouble was that of Needles
Because he can really hurt you and your party, so my best course of action was to blind him and beat him up while he couldn't see.
I was able to destroy both of his arms but the goat did get hit though blindness and died.