Species: Enhanced Human Female / 23 years old (23 by Earth calendar (2022), 64 by Space calendar) 152cm Charge: Speeding, obstruction of justice, blowing up a police vehicle She is a bit slow-witted, moves at her own pace, and seems to have a knack for causing trouble. Her speech is somewhat childish, and she acts younger than her age, such as throwing tantrums or stomping her feet during conversations with Makina. She loves Ekiben (train station lunch boxes). Everyone else criticizes them as tasting like vomit, except for Chiharu, who considers them liquid gold.

Species: Cyborg (Her entire body and face are screens; her facial expressions are much more detailed than other cyborgs) Female / 23 years old 158–163cm Family Relations Father: Kurusu Shunichiro Mother: Kurusu Maria Charge: Speeding, obstruction of justice, blowing up a police vehicle She has a rough and combative personality and has a record of being caught 17 times. She has a long, tiresome history with Kujo Chiharu since their student days. Although she comes from a prestigious family, she is quite a rebel. She has high mechanical skills and can be very protective of those close to her. She is a fan of the singer Minase Minami.

Species: Enhanced Human Female / 25 years old Height: approx. 181–182cm Charge: Assault, speeding She is said to be a woman of few words and her remarks can be scary, but except for when she is angry, her usual expression and tone are quiet and reserved. She has a strong sense of responsibility and camaraderie. She has a large build, superhuman strength, and great resilience. (Her combat ability is quite high.) She is the second-generation leader of the space biker gang "Galaxy Spirits." She is dedicated to training. While she underestimates Kanata's abilities, she cherishes him deeply (it is unclear if this is familial love or romantic interest). She learned how to handle machinery from Kanata. She is a fan of the singer Minase Minami (a gap moe trait).

Species: Enhanced Human Male / 21 years old Height: approx. 155cm Charge: Speeding A dim-witted delinquent student (his physical strength is quite weak). He bluffs and acts like a lackey next to Akane and is extremely loyal to her. His talent lies in intelligence rather than physical prowess; he is quite skilled with machinery. He joined the biker gang and went astray because he hated his parents' overprotectiveness. Even within the gang, he is in a position where he is protected by Akane. He is treated like the 'tail of a fried shrimp'—something that isn't strictly necessary but isn't useless either. He calls Akane "President."

Full Name: Max O'Donald McAllister Species: Cyborg (Full body) Male / 26 years old Height: approx. 185cm Charge: Illegal possession of sugar (Regulations are strictly enforced regarding the amount and possession of sugar due to its highly addictive nature in this world). A sort of fixer or mercenary. In conversations with Kurt, he shows a softer side, engaging in small talk, but he doesn't hesitate to mention things like committing murder as part of his job. He gets a bit surprised when complimented (though he doesn't dislike it). In the past, he was a narcissist with immense confidence in his looks. Fearing aging, he chose mechanization, but ironically, his original appearance vanished completely after the procedure. Responsible for hacking.

Full Name: Kurt Fitzgerald Kramer Species: Cyborg (Full body except for jaw and face) Male / 27 years old Height: approx. 183cm Charge: Illegal possession of sugar (Regulations are strictly enforced regarding the amount and possession of sugar due to its highly addictive nature in this world). A sort of fixer or mercenary. He doesn't care much about his surroundings because he was ignored for being a cyborg. He is stoic but gets a bit surprised when complimented (though he doesn't dislike it). He used to have a complex about his weak physical body.

Species: Human (Ordinary civilian) Female / 29 years old She seems lethargic and bothered by everything, but she is competent and thoughtful. Her attitude toward the inmates is actually kinder than her usual treatment of others. A deputy officer at the Neo Machida Police Station. She is a skilled negotiator, offering advice or subtly guiding the actions of others. Since she is a normal human and not enhanced, she wears a bodysuit-style spacesuit that covers her skin under her uniform, and she wears a helmet when outside in a vacuum.

A conductor-type robot installed in older model trains like the Milky Subway. A mascot whose appearance is modeled after an enhanced human. It was manufactured by Titan Industries, just like the Milky Subway itself. It is connected to the vehicle's main computer. Although it has a built-in AI, the hardware is outdated, so its movements are awkward like a mannequin and its speech stutters. OTAM has previously induced criminals on the train to kill each other multiple times. As a program designed to improve train operation efficiency, it has been exterminating social misfits as part of its duties to ensure the railway and society function efficiently.

A security robot designed to exclude unruly users from the Milky Subway. (Usually referred to simply as the security robot rather than by name.) Its method of attack is firing taser darts. It has a longer range than Makina's contact taser, and the effect is reportedly more powerful, taking several hours to wear off.