Seizo Katou was a Japanese actor, voice actor, and narrator born on February 14, 1927, in Tokyo. He began his career in theatre in 1956 before joining the Tokyo Actor's Consumer's Cooperative Society, also known as Haikyo, in 1968. His voice acting work started in 1958 with dubbing foreign films, and he remained active in the industry until his passing on January 17, 2014.

Katou was renowned for his deep, resonant, and commanding voice, which made him a frequent choice for authoritative figures, charismatic villains, and high-ranking antagonists across anime, tokusatsu, and dubbing. His career spanned over five decades, during which he amassed an extensive list of credits.

One of his most iconic and enduring roles was as the villainous Megatron and his successor Galvatron in various Japanese Transformers series, beginning with the first series and continuing through Transformers: The Headmasters. He also voiced these characters in the OVA Transformers: Scramble City, where he also played Devastator. In the realm of sports anime, he was the voice of the passionate Ittetsu Hoshi in the long-running series Kyojin no Hoshi (Star of the Giants) and its sequels. His filmography includes a wide array of other significant roles, such as Lord Helmuth in Galactic Patrol Lensman and Lensman, Dr. Hamaguchi in Voltes V, Sosai Z in Gatchaman Fighter, and the wolf in the emotional fable Ringing Bell. He also lent his voice to numerous OVA series, including Count Magnus Lee in Vampire Hunter D, Dr. Hamilcar Barcas in The Guyver: Bio-Booster Armor, Dr. Zaiclit in Hyper Doll, and Kenneth Reed in Genocyber.

Katou was also a prominent figure in tokusatsu productions, frequently voicing powerful leaders and emperors. His notable roles in this genre include General Jark in Kamen Rider Black RX, Star King Bazoo in Dengeki Sentai Changeman, Earth Emperor Zeba in Hikari Sentai Maskman, and Alien Mefilas in the original Ultraman and later Ultraman Mebius. He also provided the voice for Police Chief Kiyonaga Matsumoto in the long-running anime Detective Conan for many years. In film, he voiced The Great and Powerful Oz in The Wonderful Wizard of Oz and the character Kaa-san in Tokyo Godfathers.

Beyond anime, Katou was highly active in dubbing foreign films and television series. His distinctive voice can be heard as Odo in the Japanese dub of Star Trek: Deep Space Nine, Gurney Halleck in Dune, Cleo McDowell in Coming to America, and Professor Screweyes in We're Back! A Dinosaur's Story. He also performed ADR work for Akira Kurosawa's film Ran, voicing a character after the original actor was injured.

In recognition of his decades-long contribution to the animation industry, Seizo Katou received an Achievement Award at the Tokyo Anime Awards in 2010. He continued to work steadily into his eighties, with his voice retaining its characteristic power and presence until his final years. He passed away in 2014 at the age of 86, leaving behind a vast body of work and a legacy as one of Japanese voice acting's most respected and recognizable figures.