Niccolo serves as an assistant and heavy for Tujiro XIV, a vampire who runs a kabuki troupe as a cover for a slaving ring. He often works in tandem with Yoshi Onagawa.
Christine Spar, the second Grendel, is hunting Tujiro and his troupe because they kidnapped and killed her son Anson. She spies on them and learns their habits, then breaks in to their hotel room. Tujiro, Niccolo, and Yoshi confront her. Spar takes out the lights, but Niccolo can see in the dark with his infra-red glasses. However, she rams him in the mouth with the blunt end of her staff, smashing his teeth. Tujiro throws her out of the window. Chris later kills Yoshi in response.
Chris later bugs their car and finds out that Tujiro wants Niccolo to kidnap Brian Li Sung, her new friend, and sell him to an international slaving ring. Chris keeps Brian away from the place they were going to kidnap him from, thereby temporarily saving him, but now has to worry about keeping him safe as well as getting revenge for Anson. She doesn't tell him what's going on because she knows he won't believe Tujiro is a vampire.
After a couple more confrontations with Tujiro, they make plans for a final battle at Brian's apartment. Brian now realizes and accepts what's going on. Tujiro breaks in through the window, and Niccolo comes in through the door, dressed in a ridiculous jacket and armed with claws strapped to his hand. He's slavering and wild. After spraying Tujiro with water, Spar quickly chops off his claw hand with the fork, slices through half of his brush-top hair, and once again rams him in the mouth with the blunt end of the fork. Amazingly he's still standing, and grabs Brian from behind. Brian, who knows Tai Chi, elbows him in the gut and punches him against the broken window. Chris and Brian later manage to get Tujiro to run off.
Niccolo is later seen running out of the apartment clutching his bloody stump. Detective Riley sees him and calls his location in to the police, who arrest him and take him in to custody.