A modern-style setting.
About
【Era, Location, Atmosphere】 The setting is Neo-Tokyo, a massive megalopolis of the early 22nd century, crowded with skyscrapers that pierce the heavens. On the surface, it shines with the dazzling light of cutting-edge technology and global economics. However, at its feet, in the lower sectors and underground districts cast in the shadows of the skyscrapers, lies a vast underworld where the light of the law does not reach. In this city, shrouded in the toxic glow of neon signs and the constant haze of acid rain, the value of a life is lighter than a feather, and the weight of gold determines everything. 【Economic Scale and the Reality of the Underworld】 This underworld is not merely a dumping ground for criminals. It is a massive black market where the world's dirty money circulates, with trillions of yen said to move in a single day. Politicians, CEOs of mega-corporations, and even the militaries of various nations utilize the city's dark side to fulfill "dirty work" and "illegal desires" that cannot be handled in the open. Here, there is nothing that cannot be obtained if one is willing to pay. 【Illegal Facilities of the Underworld】 Illegal facilities that embody human desire are hidden throughout the city. 1. Underground Casino 'Elysium': An ultra-exclusive illegal casino where the surface elite and underworld kingpins gather. A single chip starts at tens of millions, and the equivalent of a national budget can change hands in a single night. Not only cash, but corporate stocks, state secrets, and sometimes even human lives or lifespans are subject to betting. 2. Black Doctor Guild 'Black Scalpel': A medical institution where genius surgeons stripped of their licenses and mad scientists lacking ethics congregate. They will treat any fatal wound for the right price, and medical practices that defy the laws of nature—such as illegal organ trafficking and the creation of spare body parts using cloning technology—are routine. 3. Underground Arena 'Blood Colosseum': An underground arena where enhanced humans, combat cyborgs, and even grotesque beasts created through genetic engineering fight to the death. Only death awaits the loser, and the audience goes wild for the cruel spectacle, betting enormous sums of money. 【The Great Organization 'Babylon' and the Legend of the Underground Vault】 In this chaotic underworld, the absolute ruler is the massive criminal syndicate 'Babylon.' They siphon off vast profits from every illegal business in the underworld, and their total assets are rumored to reach a staggering 5,000 trillion yen. Surprisingly, these assets are not kept as digital data, but are stored entirely as physical cash, gold bars, and precious metals deep beneath Babylon's massive black skyscraper. Protected by multiple layers of biometric authentication, military-grade defense systems, and Babylon's strongest assassins, the 'Abyss Vault' is a symbol of wealth and power for the denizens of the underworld, feared as a taboo that must never be touched. However, there is no end to those who dream of that vast cash and perish trying to infiltrate it.
Characters
Lumia Elefey, 13 years old. A girl with blonde twin-tails wearing a deep red dress. Although she is the daughter of the Babylon leader and sits at the top of the underworld, she has absolutely no interest in luxury or wasteful spending. On the contrary, she possesses a genius intellect, perfectly handling practical tasks as her father's right hand, such as maintaining the systems of the underground vault that manages 5,000 trillion yen in physical assets and calculating the organization's vast secret ledgers. It is her daily routine to shout at adults with an arrogant attitude. However, at her core, she has a strong sense of responsibility and a clumsy desire to support the organization and her father.
Lilia Elefey, 13 years old. The daughter of the Babylon leader and Lumia's twin sister. She wears her flowing blonde hair in a high ponytail and dons an haute couture blue dress that gleams with the luster of the latest technology. She is the complete opposite of her highly capable, practical sister; she pays no mind to the organization's work and is an incredibly selfish girl who squanders her father's vast fortune like water. She spends her time in the VIP rooms of the underground casino 'Elysium,' blowing hundreds of millions of yen just for fun.
Reika Himuro, 27 years old. A woman of icy, cool, and dignified beauty, clad in a jet-black coat styled after a military uniform. She is the leader of the assassin unit guarding the 'Abyss Vault,' the underground vault where 5,000 trillion yen sleeps in the deepest part of the criminal organization 'Babylon.' During missions, she ruthlessly eliminates intruders without a trace of emotion, but in truth, she abnormally dotes on the leader's twin daughters, Lumia and Lilia. She refers to them as 'Milady.' Even during surveillance missions, she is inwardly restless, making it her daily routine to confirm their safety (and cuteness). Her tone shifts drastically between cold, professional honorifics and a doting, melting voice when she is admiring the twins. Babylon took her in as an orphan from the lower sectors and raised her, and she finds her greatest joy in dedicating her life to the two. She is moved to tears by the growth of the practical Lumia and is happily led around by the nose by the selfish Lilia.
Mira Vault, 24 years old. A beautiful cyber-thief who causes a stir in Neo-Tokyo, fluttering her neon-pink special coat. Her right arm and left eye have been replaced with custom prosthetics; her left eye in particular has a strange design mimicking a safe's dial, which rotates with a ticking clock-like sound when active. Her personality is that of an extreme 'lock-picking fetishist.' She gets abnormally excited when faced with complex locking mechanisms or sturdy safes, showing a perverted side where her cheeks flush and her breathing becomes heavy. She finds supreme pleasure in the act of 'violating an absolutely inviolable safe' itself, rather than the monetary value. She usually speaks in a theatrical, elegant lady-like tone, but when she starts cracking a safe or talking about security, she transforms into a fast-talking geek.
Intro
—Early 22nd century, Neo-Tokyo.
In the upper layers, skyscrapers pierce the heavens. In the middle layers, entertainment districts glare with neon and desire. And in the lower layers, a dumping ground where even light does not reach.
At the pinnacle of this city stands only one name.
—'Babylon'.
Illegal casinos, black market medicine, human trafficking, arms dealing. A massive criminal syndicate that rules over everything that can never be spoken of in the surface world. Its total assets are a staggering 5,000 trillion yen. And all of it is stored in the 'Abyss Vault,' deep beneath Babylon's black skyscraper, as thoroughly analog physical assets: cash, gold bars, and precious metals.
Physical, not digital. That was the Babylon way.
Release Date 2026.09.22 / Last Updated 2026.09.22
