Professor Saotome founded and directed the Saotome Institute, researching Getter Rays and developing the Getter Robo series. His initial aim of creating Getter machines for space exploration shifted to planetary defense against existential threats. He had three children: Tatsuhito, Michiru, and Genki. Tatsuhito died during a Hyakki Empire attack on the institute, deeply affecting Saotome despite his outwardly pragmatic demeanor.

He appears as an elderly man with gray hair and a beard, typically wearing a white lab coat, shirt, tie, pants, and traditional geta. During early operations, he briefly wore a yellow pilot suit. His personality blends pragmatic ruthlessness with underlying compassion; he authorized lethal force testing on potential pilots like Ryoma Nagare and eliminated compromised staff, including his own son, to prevent wider harm. Privately, he mourned these losses while maintaining hope for humanity's future. His obsession with Getter Rays intensified over time, contributing to later mental instability.

His scientific expertise established him as the foremost Getter Ray authority, enabling advancements like Getter Alloy and successive Getter Robo models. He identified and recruited key pilots through unorthodox methods, directly overseeing critical projects including the original Getter Robo, Getter Robo G, and Shin Getter Robo. During the Dinosaur Empire conflict, he coordinated defenses and approved Musashi Tomoe's sacrificial plan to destroy an enemy army using Getter Robo.

In the *Shin Getter Robo* manga continuity, prolonged Getter Ray exposure accelerated his mental decline. He foresaw invasions by extra-dimensional entities and pressured Ryoma and Hayato to pilot Shin Getter Robo despite their reservations. During the Andromeda Stellaration's assault on his institute, he urged Ryoma into battle, subsequently fusing with the Getter Rays alongside his staff and family as the facility was destroyed.

The *Getter Robo Armageddon* OVA presents an alternate narrative where his daughter Michiru's death during Getter Robo G testing—caused by prior Invader infection—drove him to combat the Invaders. He became infected himself, was resurrected as their puppet after Hayato killed him, and deployed mechanized forces against humanity. In his final battle against the Getter Team, he used psychological attacks based on Michiru and Musashi's deaths. Near his end, he regained autonomy, thanked the team for stopping him, and perished destroying the controlling Invaders.

Within the *Getter Robo Arc* timeline, he died years earlier during the Andromeda Stellaration's initial attack. Benkei Kuruma's emergency deployment of Getter Dragon caused a catastrophic overload that destroyed the institute, killing Saotome alongside researchers. His legacy endured through the incomplete Getter Robo Arc, which he designed as humanity's final safeguard against the Andromeda Stellaration. Hayato Jin, succeeding him as institute leader, referred to Arc as "the last of Saotome's machines," signifying his role as Saotome's successor and his deep respect for the professor's work.

His influence extended beyond technological contributions; his ethically ambiguous decisions and unwavering commitment to defeating threats using Getter technology shaped Hayato's leadership approach and the institute's operational philosophy. Posthumously, his spirit appeared in *Getter Robo Go*, encouraging Hayato to pilot Shin Getter Robo during a crisis.