It was just never revealed, as they always tried to find a way to send Vlad away, secretly researching for a period of time while Vlad was unaware.
However, they were not aware that even the vines supporting this cave, and even the Fungus Blanket they were researching, were watching them, so their concealment was essentially a joke.
Research, in essence, is merely a summary of experiences and natural laws. But when natural laws themselves can change, there is no basis for research.
Under the guidance of the Fungus Blanket's consciousness, their research on the Fungus Blanket made almost no progress. The only thing they could confirm was, through their own Divine Arts, that all these plants shared a common composition.
It wasn't until they researched for several days without any results that they finally decided to bring the matter to the forefront.
