Chapter 551 Mysterious Old Man

Du Fei's gaze was firmly fixed on the horizon, his aura subtly surging. After advancing to the sixth-grade high-level of the Pill Master Realm, he had noticed that the space in the sky seemed somewhat abnormal, with a faint, eerie aura emanating from it. As his Martial Cultivation also progressed, this sensation grew even stronger! It's worth noting that Du Fei had been cultivating here for half a year, and no one had ever appeared. However, at this moment, he detected this anomaly.