Dr. Saotome directs the Saotome Institute and stands as the foremost expert on Getter Rays. He created Getter Robo technology and fathered Michiru, Tatsuhito, and Genki Saotome. Before the story begins, his daughter Michiru died during a Getter Robo combining accident involving pilots Ryoma Nagare and Hayato Jin. Convinced this was deliberate, Dr. Saotome developed a profound grudge against them. He was later seemingly murdered, with Ryoma framed for the crime.

After his apparent death, Dr. Saotome emerged alive, allying with the Invaders, shape-shifting aliens that possess and mutate humans. He initiated global threats using his ultimate creation: Shin Dragon, a colossal bio-organic weapon fueled by cosmic Getter Rays. This forced Ryoma's release from prison to confront him. When nuclear missiles struck Shin Dragon, the resulting explosion and Getter Ray shockwave annihilated roughly 99% of humanity, an event known as "Armageddon."

Thirteen years after Armageddon, Dr. Saotome continued his collaboration with the Invaders. Scientists Mr. Stinger and Mr. Cowen, who allowed Invaders to possess them, assisted him. Together, they pursued a plan to transform Jupiter into a Getter Ray Sun while hurtling its moon Ganymede towards Earth. His actions were driven by vengeance for Michiru's death and a distorted vision of Getter Ray-driven evolution.

Dr. Saotome's younger daughter, Genki Saotome (later known as Kei Kuruma after trauma-induced amnesia), became a pilot for the new Getter Team opposing him. He also created the artificial human Go Saotome to control Shin Dragon, though Go eventually defected to protect Kei. Dr. Saotome was last seen merging with the Getter Rays during the final conflict, becoming one with the energy he devoted his life to studying. His legacy endured through Hayato Jin, who later led Saotome Labs and developed new Getter units, explicitly calling Getter Robo Āḥ "the last of Saotome's machines."