Igor's assumptions or conjectures, regardless of what they were, were incredibly convincing. Otherwise, Joseph and Kuren wouldn't have, by coincidence, described the same features of the creatures on Guru Mountain.
If Igor were the enemy, then Joseph and Kuren would become sinners to all of Guru Mountain. But luckily, Igor wasn't.
As Igor listened and thought, he realized there were only two ways to prove his conjectures correct. One was to find relevant evidence. The other was to pursue his line of reasoning to its conclusion.
Finding evidence might seem simple, but within the World Setting Technique, it wasn't as if one could do whatever they wished. However, continuing along the path of his conjecture held some possibility because, simply put, the World Setting Technique was a type of spell. Appropriately using Spirit Power to explore within the technique was exactly what Igor excelled at and enjoyed doing.
