"Vengeful Spirit..."
Tao Yu remembered that one of the subsequent steps in the Art of Corpse Refining was that if zombies wanted to further elevate themselves, one of the options was to integrate with vengeful spirits; however, he did not possess the Spirit Control Technique.
When he was in Monster World, he obliterated a boss who had the potential to be a Fortune Thief, and after merging into Wino's corpse, it turned into a storage vessel.
And these two were undoubtedly a legitimate combination of vengeful spirit + zombie.
"Zombies are tough and resilient, while vengeful spirits are unpredictable and changeable; without the understanding of a Grandmaster, even first-rate experts would struggle significantly."
As Tao Yu beheld the occasional appearance of a female ghost within his aura, he pondered deeply.