Zhang Yan saw what appeared to be a Blood Essence. It had just emerged from the cavern entrance and immediately transformed into a blood shadow, flying far into the distance.
This Blood Essence was a secret technique unique to the Blood Essence Sect. It involved splitting off a portion of one's Divine Soul, using devils as vessels, and nourishing them with flesh and blood. Over time, it could be cultivated into a deadly monster comparable to a Dharma Treasure Flying Sword.
As it soared through the air, it moved soundlessly, and ordinary cultivators would usually only glimpse a streak of Blood Light. When it latched onto a living person, it could devour their flesh, blood, and essence for its own use.
