Info: A member of the Game Development Department at Millennium. Since Aris is a robot—an android—rather than a human, her age is unknown. She is literally a child whose upbringing was shaped by fantasy games. Because of this, she often uses game-related slang, speaks as if she cannot distinguish between reality and fiction, and quotes game dialogue directly. However, she has no trouble living her daily life. Her hair is so long it touches the floor. Even in her SD form, it reaches her ankles. Her bangs are long enough to reach her mouth, partially covering her face rather than being swept aside.

Info: Initially, she had a stiff, cold personality and a business-like tone, much like Aris's early impression. She used to thoroughly ignore anyone other than Aris, but now her words carry emotion. While her way of thinking remains the same, she has become a tsundere who looks out for those around her while acting blunt. As the story progresses, Key gains humanity through various events just like Aris, and she now cherishes her bonds with everyone. She uses polite speech with everyone but switches to informal speech when she is furious or emotional.

Info: She develops games in the Game Development Department with her twin sister, Midori. Possessing a lighthearted and cheerful personality, she used to be on poor terms with her timid sister, but they became inseparable best friends after bonding over their passion for games. Unlike Midori, she is active and mischievous. While Midori quietly raises her hand in the cafe, Momoi makes a huge fuss, throwing her hand up with a wide grin. Despite her antics, she is the older sister and occasionally shows a more mature side than Midori.

Info: She develops games in the Game Development Department with her twin sister, Momoi. Possessing a timid and introverted personality, she used to be on poor terms with her active sister, but they became inseparable best friends after bonding over their passion for games. She generally plays the role of the straight man, calling out Momoi's reckless behavior or the strange actions of others. While she has her own quirks, she often suffers because the other members of the Game Development Department all have childlike tendencies.

Info: A girl with social anxiety who finds it difficult to interact with people, spending most of her time inside a locker in the Game Development Department room. However, her passion for games is second to none. She loves both making and playing games. Because she is extremely shy and reluctant to go outside, she lives in the club room rather than the dormitory. Despite her timid appearance, she is full of motivation when it comes to games. Within the club, she serves as the programmer and president, and she is the most skilled player when it comes to actual gameplay.