Slay Demons, Gain Power: Starting as a Constable on the Path to Sainthood

Also known as "All Demons Must Die." The false demon hunters: diligent, devoted, praying for a world without demons. The true demon hunters: no demons in the world? Then raise them ourselves, and let chaos reign across the land. Gu Ming transmigrates into a world overrun by monsters and demons, and unexpectedly awakens the Demon-Slaying Tome—a mystical record that devours demons' lifespans and burns his own fate to accelerate his cultivation progress. With this scroll in hand, he vows to slaughter every demonic fiend under heaven. In this world, any sentient being with wisdom can become a demon. Humans, as the foremost of all creatures, harbor darkness in their hearts—and those who give in to it are no less than demons themselves. If it is a demon, it must die. But what if he himself becomes the greatest demon of all? Then who could possibly slay him? (Note: The protagonist's personality is, shall we say, rather twisted—reader discretion is advised.)