Most of the important and valuable documents were guarded with a layer of seal. To access any of these, one had to have a higher level of spirit power than these seals.
William even heard later on from the masters who laughed on his failed visit that many documents were guarded with enchantments that would attack the spirit master if he tried to open the seals.
William didn't know who left such seals behind, and he knew no one in the academy knew as well. According to the stories he heard from back then, this library was established by a mysterious old headmaster, one that no one recalled his name right now.
William could guess the value behind such seals. It wasn't done to just annoy the disciples, but to limit anyone from knowing something that was way beyond his current powers or abilities.
And that meant for the past porter of him to end up having nothing to learn from this place.
