The Myriad Spiritual Sword Array is a supreme treasure of Emperor Tian Yuan. It is a powerful killing array. However, in order to activate, the array needs to absorb a large amount of Heavenly Energy.
After meeting Nie Li, Emperor Tian Yuan's remnant of intent decided to pass the array on to him. Since Nie Li was not yet strong enough to control the array, Tian Yuan left a part of his intent within it. If Nie Li must activate it, he can use the intent to contact Tian Yuan to activate it.
During Nie Li's battle against the Sage Emperor, many experts and treasures appeared to support him. The Myriad Spiritual Sword Array was one of those treasures. Even though it was only a single treasure, it’d killed five of the Sage Emperor’s Deity servants.