Dr. Atom Akihabara, more commonly known as Dr. Aki or by his nickname Dr. Medarot, is a foundational figure in the world of Medabots. His primary designation is that of a visionary and eccentric scientist, whose genius is responsible for much of the technology that defines Medabot society. Physically, he is depicted as an old man who is nearly bald with white hair, and he is almost never seen without his signature sunglasses and laboratory clothes. While he often acts in a goofy, forgetful, or even foolish manner, this behavior masks a brilliant and highly strategic mind.

His background is rooted in the very creation of Medabots. Alongside his colleagues Dr. Hushi and Dr. Armond, he developed the fundamental concepts of how a Medabot operates. His specific inventions include the Muscle Cable, which is used in Tinpets, and the Neuron Fiber Resin Polyester used in Medabot armor. He is also credited with inventing the Medawatch, the primary device used to control and interact with Medabots. As the world's foremost expert on Medabots, his motivations are complex, driven by both a passion for innovation and a deep-seated caution regarding his own creations.

A central motivation for Dr. Aki is the management of Rare Medals. Recognizing the immense danger these powerful artifacts pose, he secretly employs the Phantom Renegade to steal them and keep them from falling into the wrong hands, a proactive measure to prevent catastrophic events. Despite his wealth from his discoveries, he is known to be frugal, especially when it comes to others, and has a notable fondness for pudding. His role in the story is often that of an enigmatic supporter. He discreetly assists young Medafighters like Ikki Tenryou, for example, by providing him with a prototype Medawatch capable of unlocking the powerful Medaforce ability. He also serves as a source of knowledge and investigation, looking into anomalies like electromagnetic storms that disrupt Medabots.

His key relationships include his family and his scientific peers. He is the grandfather of Nae Aki, who is also a talented scientist and mechanic. In the anime continuity, he is also the great-uncle of a character named Karin. Professionally, he and Dr. Hushi were students together under Dr. Gengoro Fushihara. Later, a major ideological clash with another scientist, Dr. Maizuru, over ethical design principles led to Maizuru leaving to create the destructive Death Medabots, also known as Kilobots. He also has an adversarial relationship with the villainous Dr. Meta-Evil, who once framed Dr. Aki for arson by programming false information into a robot parrot, leading a Medabot named Rokusho to seek revenge against him.

Dr. Aki’s character experiences development primarily through the fluctuations of his reputation and the unfolding consequences of his past actions. While widely respected, his secretive methods and the false accusations against him temporarily put him in danger or cast doubt on his integrity, though his essential nature as a fundamentally ethical scientist who prioritizes safety and progress remains constant. His notable abilities extend beyond his mechanical and scientific genius. He possesses a deep, intuitive understanding of Medabot technology, allowing him to theorize about complex phenomena and develop solutions, often with a mysterious and detached air. His tendency to appear as an idiot is perhaps his greatest tool, allowing him to be underestimated while he orchestrates events from behind the scenes.