Koji Ishii is a veteran Japanese voice actor and narrator born on July 1, 1960, in Wakayama Prefecture, Japan. His real name is Koji Ishii, written with different characters. He began his career in 1988 after graduating from the Mifune Arts Academy and initially worked as a stage actor before transitioning to voice acting. Throughout his career, he has been affiliated with several agencies, including Ken Productions, and as of his later career, he works as a freelancer with a business tie-up to AMBERnote, though he was also listed with Vi-Vo.

Ishii is known for his deep, resonant, and powerful voice, which has made him a frequent choice for mature male roles, including both authoritative heroes and intimidating villains. He is also a highly sought-after narrator for television programs, documentaries, and commercials. His versatility allows him to portray a wide spectrum of characters, from the hot-blooded hero Koutaro Taiga in The King of Braves GaoGaiGar to comedic and eccentric figures like the perverted teacher Kimura in Azumanga Daioh and the eccentric Lory Takarada in Skip Beat!.

His career spans numerous notable anime roles across several decades. Some of his most recognized performances include Silva Zoldyck in the 1999 Hunter × Hunter series, King Hamdo in Now and Then, Here and There, and the flamboyant Garterbelt in Panty & Stocking with Garterbelt. He has also played significant villainous roles such as Prime Minister Honest in Akame ga Kill! and Dordonii Alessandro Del Socacchio in Bleach. In long-running franchises, he has voiced Fisher Tiger in One Piece and took over the role of Ginzo Nakamori in the Detective Conan series following the passing of Unsho Ishizuka. He also played the role of Ishihara in the series Rainbow: Nisha Rokubō no Shichinin, as listed in the user query.

Beyond anime, Ishii has a prolific career in video games. He is particularly famous within the fighting game community for his portrayal of the violent ruffian Ryuji Yamazaki and the elderly martial artist Sokaku Mochizuki in SNK's Fatal Fury and The King of Fighters series. He also voiced Gato in Garou: Mark of the Wolves. Other prominent game roles include Ikutidaal in the Harukanaru Toki no Naka de series and Blex Forer in the Zeta Gundam video games. He also has a presence in tokusatsu, notably providing the voice for Chief of Staff Damaras in Kaizoku Sentai Gokaiger and voicing characters in recent Kamen Rider films.

Ishii's career is also marked by his work in dubbing foreign films and series, where he is the regular Japanese voice for actors like Samuel L. Jackson. He has also taken over roles from his mentor, the late Kenji Utsumi, inheriting the part of Garland in the Dissidia Final Fantasy series due to their similar vocal tones. His training under Utsumi at Ken Productions was a formative period in his development as a narrator and voice actor. With a career spanning over three decades and hundreds of roles, Koji Ishii remains a respected and enduring figure in the Japanese entertainment industry.