Iemasa Kayumi was a highly respected Japanese actor and voice actor, renowned for his deep, commanding voice and his portrayals of dignified, often villainous, or authoritative characters. Born on October 31, 1933, in Tokyo Prefecture, he began his career as a stage actor in the shingeki theatrical movement before transitioning to voice work in 1956. He was affiliated with 81 Produce at the time of his passing on September 30, 2014, after a career spanning nearly six decades.

Kayumi's extensive filmography includes some of the most iconic roles in Japanese animation. In theatrical films, he is celebrated for his work in Hayao Miyazaki's Nausicaä of the Valley of the Wind as the cunning Kurotowa and in Mamoru Oshii's Ghost in the Shell as the enigmatic Puppet Master. He also lent his voice to major franchises, playing Paragus in Dragon Ball Z: Broly - The Legendary Super Saiyan, Nefertari Cobra in the One Piece film series, and James Black in numerous Detective Conan movies, a role he originated in the television series and continued until his death. His film roles also include the Baron in Oblivion Island: Haruka and the Magic Mirror and Oswald Whistler in Professor Layton and the Eternal Diva.

His contributions to television anime were equally prolific and began in the 1960s. Early in his career, he played Fudō in Ninpu Kamui Gaiden and Chief Kaizu in Fight! Osper. He was a regular presence in the works of renowned director Hayao Miyazaki, voicing Lepka in Future Boy Conan. In the 2000s, he gained a new generation of fans as Dr. Nanakamado (Professor Rowan) in Pocket Monsters: Diamond & Pearl, as the villainous Father and the narrator in Fullmetal Alchemist: Brotherhood, and as a recurring character in the Lupin III franchise. He also appeared in historical epics, such as the Sangokushi film series, where he voiced both Chen Gong and Lu Su.

Beyond anime, Kayumi was highly active in dubbing foreign films and television series. He was the official Japanese dubbing voice for Frank Sinatra and Donald Sutherland for many years. His other notable dubbing roles included Saruman for Christopher Lee in The Lord of the Rings film trilogy and Magneto for Ian McKellen in the X-Men series. In the realm of video games, he was known for his collaborations with game designer Hideo Kojima, appearing in Policenauts, and for his long-running role as the sophisticated vampire Slayer in the Guilty Gear series, a part he played from Guilty Gear X2 in 2002 up to Guilty Gear Xrd -SIGN- in 2014.

Known for his precise and unwavering professionalism, Kayumi was dubbed a "precision machine" by fellow voice actor Norio Wakamoto, who noted that Kayumi never made a mistake during recording sessions. His distinctive voice and ability to imbue characters with gravitas and complexity left an indelible mark on the anime and dubbing industries, influencing younger generations of voice actors.