Mitsuteru Yokoyama was a seminal Japanese manga artist born on June 18, 1934, in Kobe, Japan, and he passed away on April 15, 2004, in Tokyo. He is widely recognized as one of the most significant and influential figures in the history of manga and anime, credited with pioneering and establishing several major genres.

Yokoyama began his professional career after being deeply inspired by Osamu Tezuka's work. He made his debut with a story titled White Lily Story, which caught Tezuka's attention. His first major breakthrough came in 1956 with the serialization of Tetsujin 28-go, a work that became a national phenomenon and is considered a foundational text of the mecha genre, featuring a giant robot controlled remotely by a young boy. The success of this manga and its subsequent anime adaptation led Yokoyama to become a full-time artist and relocate to Tokyo, where he later founded his own production company, Hikari Production, in 1964.

Throughout his prolific career, Yokoyama demonstrated a remarkable ability to work across different demographics and genres. In 1966, he created Sally the Witch, which is recognized as one of the first magical girl manga and anime, establishing a template for countless series to follow. That same year, he began writing Kamen no Ninja Akakage, a manga that helped spark a major ninja boom in popular culture; it was quickly adapted into a successful live-action tokusatsu series in 1967, which was notable for being Japan's first color ninja TV series. He also authored Babel II, a work that helped define the supernatural psychic action genre.

Yokoyama's talent extended to literary adaptations, particularly of Chinese historical epics. His versions of Suikoden (Water Margin) and the monumental Sangokushi, which he worked on from 1971 to 1987, became immensely popular. The Sangokushi manga was later adapted into a long-running anime and earned him an excellence prize from the Japan Cartoonist Association in 1991. Other notable original creations include the giant robot epic Giant Robo, which spawned multiple sequels and spin-offs, including the original video animation GinRei. He also created the manga Mars, which was loosely adapted into the popular 1980s mecha anime television series Six God Combination God Mars, which later received an original video animation sequel titled God Mars: The Untold Legend.

Yokoyama's artistic identity was characterized by calculated storytelling and elaborate settings, often favoring serious narratives over comedy. His style was known for its relatively restrained characterizations, focusing on plot and suspense. An important aspect of his industry significance was his pragmatic and tolerant attitude toward adaptations; unlike many creators who insisted on strict fidelity, Yokoyama readily allowed his numerous works to be adapted into various formats, including anime, live-action television, and films, which greatly contributed to their widespread popularity and lasting influence. His pioneering contributions have been cited as a major influence by later acclaimed artists, including Katsuhiro Otomo and Hirohiko Araki. He continued to work until his death in 2004 following a fire at his home, having left behind a legacy as a true innovator who shaped the very structure of modern Japanese comics and animation.