[Demon Eye]
From Han Dong's unique perspective, there's more than just gill structures at the end of the mandible bone.
Even through clothing, he detected some fish scale structures spreading beneath the skin.
A 'mucous network' structure appeared in its internal organs, connecting multiple organs. In special situations, all the organs worked together in high efficiency.
However.
What puzzled Han Dong was that this middle-aged man who lived outside the city showed no signs of brain degeneration.
Without the protection from the Holy City, common people living alone outside were doomed to a fate of polluted corruption.
Han Dong had studied the brain structures of "Heretics", "Ghouls", and "Blood Descendants" in his manor... indirectly confirming that when normal organisms are polluted, the brain is the first to degenerate.