Tobrin was an apprentice of the legendary mage Miragul. In order to study under Miragul, Tobrin had to remove his own eye as an act of fealty. To cover up the wound, Tobrin created an eyepatch and imbued it with magical powers. Master T'Lys, who you met when you first landed on Everfrost, has entrusted you with this eyepatch's location and contracted you to uncover it. You must enter this domain of Tobrin and recover it.
Kill everything in sight. Once you clear one room, a door will open revealing another room with more mobs ripe for the slaughter. Once the final (northern) door is opened, confront a shade of Tobrin and loot the eyepatch from the chest in the middle of the room. Once you do this, Master T'Lys and his goons will appear at the exit of the room and attack you. T'Lys will escape, but Tobrin's Mystical Eyepatch will be yours for safekeeping!