Rintarō Nishi is a Japanese actor and voice actor born on July 15, 1965, in Osaka, Japan. His real name is Kazuaki Kurita. He is affiliated with the talent management firm Office Osawa. Nishi began his career in theater, joining the Yen Performing Group in 1991 after graduating from the Yen Acting Institute in 1988. His transition to voice acting occurred when his agency provided him with a script, and he soon became a familiar presence in anime, known for his deep and distinctive voice.

His voice is characterized as gravelly, low-pitched, and rugged, which naturally suits roles such as tough characters, yakuza members, and villains. This vocal quality has led to a wide range of significant roles across anime, tokusatsu, and dubbing for live-action films. In anime, some of his most recognized performances include Moblit Berner in Attack on Titan, the Narrator and King Bartra Liones in The Seven Deadly Sins, Jason in Tokyo Ghoul, Tetsuzaemon Iba in Bleach, and Asimov Solenson in Cowboy Bebop. His filmography also includes Free in Soul Eater, Heracles in One Piece, and Jiguro in Moribito: Guardian of the Spirit. In the series Garouden: The Way of the Lone Wolf, he voices the character Shōzan Matsuo. In the tokusatsu genre, he is well-known for providing the voice of the villain Doukoku Chimatsuri in Samurai Sentai Shinkenger and for appearing as Commander Shadam in Gosei Sentai Dairanger.

Nishi is also highly prolific in dubbing foreign films and television series. He is the regular Japanese dubbing voice for actor Vin Diesel, taking on roles such as Xander Cage in the xXx film series and Richard B. Riddick in The Chronicles of Riddick. His other dubbing credits include providing voices for actors such as Terry Crews, Paul Bettany, and Nikolaj Coster-Waldau in various films. In the realm of video games, he has contributed his voice to the Ryū ga Gotoku (Yakuza) series as Masaru Watase.

Throughout his career, Nishi has frequently collaborated with a consistent group of fellow voice actors. He has worked on numerous projects with performers such as朴璐美 (Park Romi), 三木眞一郎 (Shinichiro Miki), and 小西克幸 (Katsuyuki Konishi). His enduring presence in the Japanese voice acting industry since the 1990s, his versatility across different media, and his status as the official dub voice for a major Hollywood star are notable achievements that mark his long and successful career.