Lu Song couldn't have reached Foundation Establishment Perfection in a hundred years by relying solely on the aid of elixirs.
After all, Tong Huan's cultivation conditions were no worse than his, yet he was still only at Mid-Stage Foundation Establishment.
This could only mean that the Seven Luminaries Spiritual Body he acquired in the Ancient Secret Realm did far more than simply preserve his vitality and keep his physical body in a perpetual state of peak condition.
It made sense. On one hand, there were legacy items like the Supreme Qingwei Sword Box, the Ziwei Dazzling Thunder Sword, and the Nine Heavens Bone Forging Techniques.
On the other hand, the Black Flame infusion was clearly also prepared for the Secret Realm's heir, so it was bound to be something extraordinary.
