After martial artists die and their bodies did not decay under some special circumstances and absorb heaven and earth essence energy instead. This would strengthen their fleshy body, causing them to turn into a zombie.
At the beginning of birth, a zombie was just a walking corpse that had no consciousness. Because martial artists produce evil yin qi after death, so it kills instinctively.
Once a zombie was formed, they could seize the martial artist's essence to strengthen their own fleshy body when they kill martial artists.
This was actually a cultivation process, only that it was done at a subconscious level.
Following the fleshy body becoming more and more powerful, the zombie would even give birth to intelligence belonging to its own. This intelligence already had no relation whatsoever with the martial artist when he was still alive, becoming another lifeform.
