Feilang (緋狼, Feilang) is a freelance hitman operating in China. He is Xianming Lin's childhood best friend and partner during their training together.
He has short and ruffled red hair, with a signature scar running vertically over his left eye that he received from Lin and a bar code-like tattoo on his upper right arm. He is usually seen wearing a black tank top which has his shoulders bare completed with skinny jeans and designer sneakers. His right eye is described as brown while his left artificial eye is described as a dull black in the light novel, but in the anime both are about the same shade.
Feilang is noted to having an expressive and cheerful manner when speaking, but he has a certain madness to his demeanour. Due to his harsh upbringing in the killer training facility, he has a deep resentment for human trafficking and anyone who partakes in that business and goes as far as using sadistic methods to punish them, which is demonstrated when he sells the daughter of a former human trafficker. Similarly, he once put two people in a cage and ordered them to fight to the death to send a message to the opposing organization.
Feilang was born to a prostitute and was used to bring in potential clients to his mother's workplace. When his mother could no longer use him to make money and was more of a burden than a merit, she sold him to human traffickers. He was then sent to a killer training facility in China. By chance he happened to hear the guards mention the final exam, which required the cell mates to fight each other to the death, so he strangled his partner he was teamed up with to exempt himself from the exam.
However, a new trainee named Maomei (Xianming Lin), was brought in to replace his partner. Since he had not managed to get his way, he decided to befriend and get close to Maomei to easily kill him when the final exam occurs in five years time. Over that time he played the role of support so they could survive the daily exercises and testing they were put through and did form a genuine friendship and respect for Maomei.
The day of the exam Feilang played dumb so Maomei would let his guard down and used that opportunity to try and cut him down. Just as he was about to deliver the finishing blow, Maomei managed to grab a nearby weapon and sliced his left eye before stabbing him in a vital area. Severely injured, Feilang fell unconscious, and seemingly dead his partner Maomei was let out of their cell while his body was retrieved to be disposed of. However, when the cleaner realized Feilang was still alive he was given medical treatment and sold again to a sadistic elderly man to be tormented with. He managed to trick his owner into letting his guard down and effectively killed him. After that he began working as a freelance hitman, receiving jobs from his mediator Yang.