On the desk was the map of Pengxuan Grotto Heaven, marked with numerous areas where Secret Spirits existed, some of which were difficult even for humans to reach.
It's not that humans lack the capability to kill those Secret Spirits; with their power in the Grotto Heaven, even the strongest Secret Spirit would struggle to withstand a large-scale army siege.
The Secret Spirits that humans can't kill generally fall into two categories. One is that the environment is so special that human armies can't deploy their methods there.
The other category is that the Secret Spirits themselves are unique, either coexisting in large numbers or possessing various means of escape that prevent human armies from trapping them.
Chen Guan researched these to prepare for his own upgrade.
Although he no longer had an abundance of Heavenly and Earthly Treasures, his Creation World could now assist him in upgrading.
