Cubic Galois, known as the Solver "Edison," is a short-statured middle school student at Root Academy with short blonde hair and blue eyes. He typically wears a white shirt, green tie, light yellow vest, blue trousers, brown shoes, and a distinctive lab coat.

Initially believing geniuses shouldn't waste time on puzzles and considering numbers his only friends, Cubic focused solely on inventing robotics like his early creation Mr. Okabe. Witnessing Kaito Daimon's Phi-Brain abilities during a POG puzzle ignited a strong interest in both Kaito and puzzles, shifting him from a self-centered demeanor rooted in youth and limited social awareness. His intense loyalty to Kaito manifested in actions including stalking behaviors, such as monitoring Kaito's personal habits like shampoo usage. Peers gave him nicknames: Nonoha Itou called him "Q-chan" as a pun, while Gammon Sakanoue occasionally used "Q-taro." After losing Mr. Okabe in England, he created new robotic assistants named Mr. Yoshio and Mr. Ishimizu.

In later seasons, his role diminished; he received only one dedicated focus episode in season three, needing Kaito's help to solve a puzzle, and shared another episode with Ana Gram. He was not selected as a potential vessel for Orpheus. Before joining Kaito's group, he lived in isolation, with mathematics and inventions as his primary companions. His name references the Galois group for cubic polynomials. Moments of vulnerability included a Heroic Blue Screen of Distress after nearly dying in a puzzle designed by Rook during their childhood. He consistently used his technical skills to support the team, embodying his "Edison" title through gadgeteering.