Crado's robe. These robes were thought to have been owned by the Cathar Jedi Crado, who succumbed to the influence of the Dark Lord Exar Kun. Considering Crado was destroyed by the Cron Cluster explosion, it was improbable that he was the true owner; regardless, they were a potent, albeit corrupted, artifact that significantly boosted the wearer's strength.
The Jedi Exile may have come into possession of these robes during her journey in 3951 BBY, during the First Jedi Purge.
Within the game mechanics, only characters with a dark-sided alignment can equip this particular item.