Night Walker: Mayonaka no Tantei

NightWalker, a detective in Japan, holds a secret. Behind closed doors, he's a vampire of considerable power. Together with his secretary and partner, he solves crimes in the city and battles off the invading demons that threaten him and the city he protects. In the background, mysterious forces are at work against him, and he must keep them from harming his loved ones, all while maintaining a human appearance.