Sky Capital Underground Research Institute, Dispersing Spirit Space.
After midnight, the noises here were completely smoothed by the wind of Spiritual Energy. "Soundless" suppressed all minor vibrations and external noise transmitted through solid media—this spell, originally suitable for stealth and noiseless actions, could also serve as a sound barrier when extended to cover the entirety of the Dispersing Spirit Space.
Li Dan once asked the man, who could only perpetually stay in this underground space, how he solved the problem of being unable to sleep due to his acute hearing. The man gave two answers: either not sleep or eliminate noise.
Li Dan could only accomplish the former; the man could do the latter.
