To be frank, the Full Moon Sect was quite a long way from Yuanjiang Town, and a round trip would take a fair amount of time. For a young lady to run so far out was hardly appropriate to begin with.
That aside, the main issue was that Fu Feifei was currently only at the half-step Xiantian realm. While that was decent enough among the younger generation, it was hardly anything to write home about across the entire Sacred Land.
Having Xie Xingxuan, a Divine Awakening powerhouse, to look after her on the way to the Full Moon Sect was one thing, but once Fu Feifei had to make the return journey alone, it would be too late for regrets if she ran into danger.
Chapter 754