The Phase Lord Department needed a kinship network.
This meant that Ves would be tasked with creating a new ancestral spirit that specifically appealed to the Ascended Giants.
Well, he was already planning to create a design spirit based on the darkness element, so he may as well fulfill a second order.
Perhaps he should create additional design spirits in order to meet other needs, such as creating a design spirit centered around spearmanship.
In any case, the Dark Apostle had nothing to do with it. He was the fighter, not the creator. He may have access to all of the theory and methods required to create a spiritual product, but he lacked the skill and confidence to succeed.
Ves on the other hand lacked the fighting spirit and control over his true body to become good at fighting. He lacked the right mindset and had never seriously devoted himself to the grind needed to become a competent soldier or warrior. These were aspects that no enlightenment fruit could improved.
