Citron, the Electric-type Gym Leader of Lumiose City in Kalos, combines battle expertise with engineering talent. He frequently invents mechanical devices designed to solve problems, though these creations often malfunction or backfire. He initially hid his Gym Leader identity when meeting Ash.

His technical proficiency shines in complex repairs, such as diagnosing a microprocessor failure to fix a malfunctioning subway network. These skills also enabled him to restore the aging forestation robot Robon to working order, allowing it to complete its mission by locating and accessing a blocked underground water source to regrow a vanished forest.

Citron travels as the primary guardian for his younger sister, Bonnie. Their sibling dynamic includes Bonnie frequently attempting to find him a girlfriend despite his objections. He prioritizes her safety, demonstrated when he collaborated with Gym Leader Cilan to rescue her from a runaway subway train. Citron modified a mechanized fishing rod into a rescue tool and coordinated with Bonnie's Pokémon, Dedenne, to access the train's control panel.

While Citron naturally emphasizes logic and technology in challenges, he learns to value collaboration. During the subway crisis, he recognized the effectiveness of combining Cilan's intuitive methods with his own technical ingenuity to save Bonnie. Similarly, he coordinated multiple Pokémon to locate the underground water for Robon's project.

Beyond his Gym duties, Citron participated in significant events, including an incident in a mechanical city involving the Mythical Pokémon Volcanion and the artificial Pokémon Magearna, accompanying Ash and Bonnie.