Not a great item description, hope this helps:
"Dehkia’s Lantern is an artifact discovered in the ancient stronghold, Atoraxxion, by Lafi Bedmountain of the Secret Guards...Upon using this artifact in certain monster zones, all nearby affected monsters will awaken into a state of chaos, increasing their strength and making them repeatedly reappear after defeating them, with no waiting time...Within the game, you can find a list with all available monster zones where you can use Dehkia’s Lantern in the Monster Zone Info window. It can be found by going to the main menu (hotkey: Esc) → Adventure (F5) → Monster Zone Info...You can also click the ⮟ icon to automatically travel to the designated location where you can use Dehkia's Lantern to awaken monsters."
(https://www.naeu.playblackdesert.com/en-US/Wiki?wikiNo=346)