From the Start, a Ghost Knocks on My Door, and I Awaken the Strongest Ghost Enforcer System

The supernatural has returned, and terrifying ghosts have appeared in the human world... After Su Fan survives an incident of a ghost knocking at his door, he awakens the Ghost Constable System. As long as he stirs a ghost’s emotions, he can collect ghost energy and transform into a constable of the underworld. As yin energy erupts, supernatural incidents grow increasingly frequent: knocking in the dead of night, the stench of corpses drifting across campus, bloodstained packages, and someone who died long ago... Facing the ghosts behind these strange events, Su Fan transforms into the Black and White Impermanence, a judge of the underworld, one of the Ten Yin Commanders, one of the Twelve Ghost Generals, and one of the Five Ghost Emperors... He becomes something more terrifying than a ghost. When the world is plunged into darkness, Su Fan stands alone before millions, slaying the Yin Gods!