Demongrub Pits is a jumping puzzle located in the southeast portion of Queensdale, in a cave of the same name.
To start, go to the Swamplost Haven waypoint in southern Queensdale. From there, head east past the skill challenge to find the Demongrub Pits.
After entering the cave, immediately go right until you see this spot. Jump over to the right side, which is slightly covered by part of the cave wall.
Jump down into the next area here.
When you get to this room, navigate on the stone pillars. You’ll end up jumping back over to the right side of the image, after starting off from the left.
Jump down here and then run past the skelk. There’s a slightly covered hole that you’ll need to jump through.
The last part is filled with many ooze and two veterans. Kill them and claim your reward, as indicated by the arrow.