A corner of the underground labyrinth.
Deep within the dark, unfathomable tunnel, a series of rumbling sputter-sputter sounds echoed. Together with the dark netherwind blowing out from its depths, it was like some colossal beast roaring while exhaling long, heavy breaths through its nostrils.
The rumbling itself was not particularly frightening, but that drawn-out "breath"... was unbelievably foul.
Moreover, the stench spread an enormous distance, drifting from the depths of the tunnel all the way outside.
Any living creature that caught the foul odor carried by that netherwind would never choose to enter. The stench surpassed even the comprehension of living beings; even Demonic Beasts that had dwelled in fetid sewers their entire lives would keep their distance upon smelling it.
Yet, facing that foul netherwind, a black shadow swiftly skimmed along the wall and rushed into the tunnel.
The reason it was said to skim along the wall rather than the ground was because the black shadow itself had merged with the wall. At first glance, it resembled a flat, square shadow, but it was actually a hole growing from the wall.
Yet this "hole" could move unhindered across the wall and even adjust the depth of its interior to avoid the magical energy arrays within the walls.
If Angel and the others had been here, they would likely have recognized it at once. It was the Dog Hole they had encountered several times before, the bizarre being that had swallowed the Black Merchant and left him half-dead.
The Dog Hole sped across the wall and soon reached the depths of the tunnel.
The scene at the tunnel's end was revealed before it.
A "cliff."
Below the cliff lay an underground cavern. It was enormous, yet tightly sealed. Other than the tunnel above the cliff, there were no other