One of the men in Mu Qian Fan's team had been completely swallowed up by one of those bog holes and they could not even retrieve his body after his death.
Besides the invisible bog holes scattered across the swampy marsh, terrible beasts hid within the misty fog. The team consisting of experienced and hardy men had lost half of their men under the attacks by the ferocious Spirit Beasts who hid within the cover of the blinding fog. More terrifying than all these dangers, was the poison within the mist that was everywhere, constantly around them. They had not noticed it in the beginning, it was not until a few of them had escaped out from under the fog and noticed that the wounds on their bodies were continuing to fester and rot after the poison had spread into their internal organs that they realised just how scary a place the bottom of the Heaven's End Cliff was.