This sword was a Buddhist dharma sword named "Evil Earth Treasury."
There were many Earth Treasury Bodhisattvas in Buddhism. They had all been sent from the Pure Land of Ultimate Bliss to hell, bearing the mission of relieving suffering, saving the afflicted, and delivering all living beings. At the same time, they were responsible for suppressing hell and preventing large numbers of ghosts from invading the Yang Realm, lest yin and yang fall out of balance and all life suffer devastation.
Humans had inner demons, and so did Buddhas.
One Earth Treasury Bodhisattva had once developed an inner demon. He fell from the Buddhist path into the demonic path, tore up Buddhist scriptures, cast off his kasaya, disregarded Buddhist doctrine, abandoned compassion, and began slaughtering indiscriminately in the underworld. Countless ghosts were destroyed, resulting in an immense tragedy.
Later, Buddhism sent a great expert to defeat and subdue the Earth Treasury Bodhisattva who had gone astray, extracting the inner demon from his body.
The inner demon struggled free and escaped. Later, it merged into a sword—the "Evil Earth Treasury" in Fan Lang's hand.
This sword possessed many abilities related to hell and could unleash immense destructive power there. It was a Divine Weapon with particular limitations.
If the battle took place in hell, Evil Earth Treasury was the most suitable weapon. Its power could even surpass the Origin Evil Dragon Sword and the Immeasurable Cannon Blade.
Conversely, if the battlefield were changed to the Human Dao Plane, Evil Earth Treasury would be greatly weakened and constrained at every turn. It was a weapon specialized for its own field.
Fan Lang slashed out. The blade of Evil Earth Treasury in his hand bore a ferocious human face, which muttered heretical scriptures that defied all morality, overturning the essence of Buddhist teachings