You roll to the side and see a vulnerable spot on the monsters stomach. You quickly kill the monster using your weapon and go down the passage and through a black door at the end. As you walk through the door you see three holes in the ground. The one in the middle of the room is the biggest and a green glow is coming from it, the left one has a blue glow, and the right one has a purple glow. To continue you must jump down one of the holes.
Left hole