Unlike the Void Sovereigns who existed in the Moon Realm, people couldn't sense where the Seven Holy Spirits were.
In William's era, when Moon Realm faith was at its most rampant, Moon Realm believers often used this to prove that the faith of the Holy Spirits Church was fake. The Holy Spirits they believed in didn't exist.
However, this saying wasn't accurate because, at the very least, the power of the Holy Spirits was real and would respond to the wishes of their believers.
The most typical example was that touching the Holy Spirit Holy Emblem in the church could give one a buff that could last for a long time. This was called the Holy Spirit Blessing, and it was also one of the most direct pieces of evidence to prove the existence of the Holy Spirits.
William received a weak strengthening buff by touching this unenchanted statue.