Two distinct characters named Xiaohei coexist within Kowloon's narrative.

One Xiaohei is a young woman inhabiting Kowloon Walled City. Her petite frame frequently showcases charming Chinese-style attire, complemented by hair styled in a bun. A distinctive fang accentuates her youth and vivid expressiveness. She sustains herself through multiple part-time jobs across Kowloon establishments, including shoe stores and cinemas. Within this community, she maintains regular interactions with Reiko Kujirai and Hajime Kudou.

A separate Xiaohei manifests as a young man appearing later in Kowloon. He enters under the pretense of fire alarm inspections, enabling discreet observation of residents like Reiko and Yaomay. His presence serves investigations into Kowloon's nature, directed by Hebinuma's father. Through scrutinizing inhabitants' daily existence, he identifies the environment as 'Generic Kowloon' and reports his findings.

These two characters share only their name and setting within the narrative.