Lancelot still found it odd, his Spirit Perception hadn't detected the approach of a powerful enemy, but the next second an eerie spatial fluctuation suddenly appeared, and he realized that some indescribable, extremely sinister presence had arrived.
The surrounding shadows seemed to become thicker, the burning vines not so far off weren't as bright, and a dark mist had spread at some point, plunging everything beyond twenty feet into complete darkness. Since this darkness was caused by the mist, even creatures with dark vision couldn't see clearly into the distance.
Because they had previously fought the Giant Skull Demon wielding the Eye of Sarizdon in the Great Abyss, the group instantly noticed the change in light and darkness. They recalled what Dong Quan had said before—Valasti, the master of the Miasma Swamp, was said to have the ability to control shadows, and it must be it that had come.