The Vast Expanse School is a part of the Vast Expanse Society which resides outside of the Vast Expanse itself.
The Vast Expanse School was found and created by the first Transcendental Cultivator called Patriarch Vast Expanse. In fact, he is believed to be the creator of the entire Vast Expanse and he also some major connections with the Vast Expanse Society. The school is divided into 9 sects, which are each controlled and overseen by a 9-Essences Paragon.
The Life-Saving Treasure of the Vast Expanse School is an arm of the clone of Patriarch Vast Expanse who was extremely close to ascending as the Immortal. Although this transformation, like many others, was stopped mid-way by Allheaven, the clone still managed to imbdue his arm with pure Immortal Qi. Meng Hao had only sensed Immortal Qi similar to this on the Immortal Pillar outside of the Vast Expanse.
The school is ruled by the Sect Master, who is a peak 9 Essences Paragon and is the ruler of Vast Expanse First Sect of the Vast Expanse School. However, the sect master does not have the authority to interfere with other the eight sects. In any of the eight sects the word of that sects Paragon is the law of the Heaven. However, above the the 9-Essences Paragon are the four Potentates, untouchable existences beneath Daosource Realm, and with the appearance of Meng Hao, they now have five.