The ghost king believed that after the Zombie's crystal core was processed, it wouldn't cause human death. However, he didn't know the direction of human mutation at the moment. What if they mutated into a monster?
"How did you deal with the crystal core?"
"I soaked it in the remaining liquid of your blood, then added a purifying agent, and finally extracted it."
"Will my blood be in the merchant Union on a rainy day?"
"Impossible. We've been keeping a tight watch on your blood. Not a single drop has been leaked."
"That's it. The business Union's processing method is different from ours on rainy days. You extracted a liquid, but they directly processed the crystal core, which is still solid. It's inevitable that there will be some virus residue inside the solid, so it's not surprising that those viruses will lead to death. "