Kai Leng is a former lieutenant N7 marine and Cerberus assassin, who first appears in the novel "", as well as its subsequent sequels. Kai Leng is the Illusive Man's most trusted agent, who used him as his best infiltration and wet-work operative for over a decade, and appears in "Mass Effect 3" as one of the game's main antagonists. He wears a coat similar to Thane's over a uniform with Cerberus colors, and his face and body is equipped with visible cybernetic implants to compensate for the injuries he sustained in "Retribution" courtesy of David Anderson. Early direction of Kai Leng's concept involve inhuman-looking metallic legs and hard armor as upgrades, which were streamlined during the later period of the development cycle of "3" into a stealthier appearance along with his hairstyle, coat length and visor type.