Blood Gu, as the name suggested, were Gu Worms that could only be cultivated with fresh blood. To a Gu master, Blood Gu were nothing particularly advanced; they could refine them at will whenever they wished. However...
Xue Fuyao killed the remaining three Monster Beasts and dissected their hearts. Without exception, every heart was wrapped in a layer of Blood Gu.
Barring any surprises, all the Monster Beasts along that entire street had been the same. No wonder their hearts beat so slowly. No wonder they behaved so meekly. No wonder... they were being controlled.
Naturally, the first ones Xue Fuyao suspected of being behind this were the Ye Household. After all, in all of Qing City, only they had the ability to do it. As for why they would do such a thing...
Xue Fuyao burned all the Monster Beast corpses before her to ashes. Flesh contaminated by Blood Gu could not be eaten.
Although Blood Gu were among the more common Gu Worms, their uses were extremely varied. Aside from controlling people, their greatest use was as material and food for cultivating other Gu Worms.
Some Gu Worms could not eat ordinary food if they wanted to grow faster; they needed to eat other Gu Worms instead. Thus, Blood Gu, the easiest to refine, became ready-made feed.
Thinking of the Gu Worms of hers that had died earlier, Xue Fuyao felt the latter possibility was more likely. A powerful Gu Worm was hidden within the Ye Household, or rather, somewhere in Qing City, and these Blood Gu were being cultivated for it.
"I was just worrying about how to investigate the Ye Household. With these Gu Worms, that will be much easier."
Xue Fuyao stayed in Qing City for another two days, asking around about the Ye Household.