Twilight of the Dark Master (1997)

In the near future, the demons prepare for a new assault on earth, which is protected by the guardians, a struggle that has gone on for eons. The dark masters have found ways to release the demon inside humans, and the first victim is Eiji, just at the moment he becomes engaged. He's hidden away in a brothel while the chief demon, Takamiya, assisted by an incestuous brother and sister, Huang and Chen, perfects the process. The earth's guardian, Tsunami, teams with Eiji's fiancée to set up a final confrontation. The earth's fate hangs in the balance.