In Daoist traditions, a practitioner of the mystic arts is called a spiritual adept; in Chan Buddhism, emptiness is a profound realization.
The Spiritual Void is the celestial realm of emptiness, a hidden place where Mount Ling and Kunlun are found.
One gives rise to two, two to three, and three to all things. All things return to the One.
Thought, delusion, right thought: all are thoughts. One thought arises, and all dharmas arise; one thought fades, and all dharmas fade.
The protagonist, Nan Chuyue, begins with Confucian thought and gradually encounters Buddhist and Daoist teachings. After countless trials and experiences, he ultimately finds that “three thousand souls of the mortal world all enter the empty gate.”
The Buddha with billions upon billions of emanations...
The Buddha of one nature and three lives...
The Three Pure Ones formed from a single breath...
The four Buddhist wisdoms...
The four Confucian virtues...
The Four Fiends and Four Evils of the Demonic Cult...
They are all in this book.
This is the book I've been looking for, Don't Be a Eunuch
Not bad, really great.