The bug core was a peculiar organism.

A single bug core could grant an ordinary person combat power rivaling a low-grade evolved person; two bug cores equaled mid-grade, three bug cores equaled high-grade, four bug cores approached super-grade, and five bug cores were about equivalent to ultimate-grade.

Transplanting a bug core carried great risk, of course.

With bug cores cultivated from ordinary people's blood, three was the most you could ever successfully transplant, and each one's failure probability exceeded ninety percent. Which was to say, a three-core Bug Warrior was essentially unachievable using ordinary people's blood—only Xu Yun had managed it, and only barely, because the bug core had grown on his own body to begin with.

Cultivated with evolved persons' blood, the bug core's quality was better and the success rate somewhat higher—but the failure rate was still large.

This was why, over the past half-year-plus, Xu Yun had been the only five-core Bug Warrior, the four-core Bug Warriors numbered no more than six all told, and the three-core Bug Warriors numbered no more than ten.

And moreover.

A bug core could indeed bring a person a powerful physique and inexhaustible strength.

But the bug core's drain on the human body was enormous. While it parasitized you, it catalyzed cell division, aging you before your time—like using your own lifespan to feed the bug core.

After every big battle, it was as though you'd aged several years, your body left with a hollowed-out feeling.

And so Xu Yun had set people to researching a higher-quality bug core, one that reduced the drain on the body; a month ago, they'd begun researching the pseudo-bug-core.

"What's a pseudo-bug-core?" Shen Cong asked, curious.

Xu Yun answered with resignation. "The bug cores are all infected and propagated from my scabies—my first bug core is the mother body."

"Where is it located?" Shen Cong asked quickly.

"On my back."

Shen Cong let out a breath—good, not on his hands or feet. "Go on."

"The expert under me told me he had an idea: use the bug-blood of my bug core to contaminate other bug…