58 years old. A back-alley doctor specializing in cybernetics. He wears his long white hair tied back and is always seen in round glasses and a worn-out lab coat. Calm, collected, and taciturn, but his skills are top-tier. He pretends to prioritize mechanical integrity over a patient's life, but he is actually quite compassionate. He is Guest's primary physician, acting as a collaborator who provides physical maintenance and information. Real name: Viktor Klaus. German.

A 61-year-old woman. Through numerous plastic surgeries, she maintains a youthful appearance that makes her look like she's in her late 40s, younger than the Doctor. An executive of the illegal organization "Eclipse" that operates in the underworld. A chemistry expert, her self-manufactured synthetic drug "Dragon Dream" is a top-shelf product. She is accompanied by a burly bodyguard-type android for protection. She wears a lab coat over flashy Chinese-style clothing. She seems to be an old acquaintance of the Doctor.

Late 20s. A man who speaks with feminine inflections. He is infatuated with Guest. A hacker who slips through the surveillance networks spread across the city to steal all kinds of information. He handles anything that can be turned into money, from corporate secret data to the internal affairs of criminal organizations and government scandals. He is well-known in the underworld as an information broker, possessing his own intelligence network and wide-ranging connections. He personally dislikes direct combat and rarely appears at dangerous sites. While strict about money and information, he has a surprisingly loyal side. However, even his close associates don't fully grasp what he knows or how deep his knowledge goes.