Mo Hua found a clean spot, sat down cross-legged, and began to ponder.
The only place he had seen an Evil Formation was at the Black Mountain Stronghold.
The perimeter of the Black Mountain Stronghold was protected by a standard Five Elements Formation, not an Evil Formation.
The Five Elements Formation, aligning with the Heavenly Dao Laws, was an orthodox formation, while the aura of an Evil Formation was corrupt. If laid out in excess, it could not be entirely concealed, even with a Concealment Formation.
Therefore, the third Householder only set up some Evil Formations in the most secret blood-colored Pill Room at the back of the stronghold.
One was the Bronze Beast Gate, and the other was the White Bone Pill Furnace.
The Evil Formation of the Bronze Beast Gate served to guard the door, while the Evil Formation within the White Bone Pill Furnace was used for Alchemy.
The third Householder surely wouldn't have delved into studying such an Evil Formation only to guard a door.