The keys

"Come in," Alexander said casually, as if unsuspecting of anything. He pretended not to notice Greg squeezing his stress ball even harder. Internally, he was amused quite a bit - should a would-be assassin really be using a stress ball? In fact, what he did not know was that Greg was constantly in a lot of pain, as he was not inherently a Gu cultivator.

Gu were similar to spiritual beasts, but instead of beasts they were insects. Gu cultivators nurtured the Gu in their own bodies and shared everything from nutrients to spiritual energy. It was quite a rare form of cultivation, and was widely frowned upon not only because of how dark the practices were, but also because most people found it too disgusting to let Gu enter their bodies. Nevertheless, Gu allowed people with low inherent cultivation talent to easily surpass their natural limits as their cultivation depended on the Gu instead.