Hivax

Located in Maldraxxus. This spider can be found in a desolate, hidden valley in the mountains in the far south-east of the House of Plagues (coordinates approximately 79, 85). You can reach it by following the southern shore of the slime lake, then turn north, and find your way east through the mountains when you're able to find a pass. Nothing is marked and it looks as if the area was never completed.