Gack Mindwrecker is a powerful boss found in the swamps of the Black Curtain. He is the brother of Frash the Cold. He is one of six bosses that the Krytan Herald at the Temple of the Ages warns about. They are all much higher in level than the rest of the creatures in the area.
Location[]
The Black Curtain: Gack spawns in two places. The first is east of the exit to Talmark Wilderness in the swamps, the second is seen on the image.