Hei is the main protagonist and an elite Contractor with the Messier Code BK-201. Hei plays a gentle-hearted student from China named Lee Shengshun when undercover. He becomes an apathetic and guiltless killer when on his missions. Joining an organization of unknown ambitions known only as a Syndicate, Hei is searching for the whereabouts of his sister Pai, whom he lost several years ago when the South American gate imploded.