Keisuke Ihara was a Japanese voice actor and actor born on June 15, 1948, in Yamaguchi, Japan. His career spanned both live-action performances and voice acting, with his work in anime beginning in the late 1990s. Ihara passed away on March 24, 2017, at the age of 68.

As a voice actor, he is best known for his contributions to the long-running Detective Conan franchise. He provided voices for several characters in the series theatrical films. In 2003, he voiced Enkai in Detective Conan: Crossroad in the Ancient Capital. The following year, he played the role of Ookoshi in Detective Conan: Magician of the Silver Sky. In 2005, he voiced the character Kubo Mizu (also listed as Jin Mizukubo) in Detective Conan: Strategy Above the Depths, as highlighted in the user's query. His final known credit in the franchise came in 2010 with a role in Detective Conan: The Lost Ship in the Sky.

Beyond the Detective Conan series, Ihara's voice acting credits include a role in the 1997 television series Kindaichi Case Files, also known as The Kindaichi Young Files. In 1999, he appeared in the television special City Hunter Special: Kinkyuu Namachuukei!? Kyouakuhan Saeba Ryou no Saigo, where he played the role of Landlord Ayanokoji.

Ihara also maintained a career as a live-action actor, with credits dating back to the 1964 film Yoru no Kata (also known as Night Scandal). His live-action work continued through the 1970s and into the 2000s, with appearances in television dramas such as the Asami Mitsuhiko mystery series entries Asami Mitsuhiko 3: Karatsu Sayohime Densetsu Satsujin Jiken in 1996 and Asami Mitsuhiko 30: Tenkawa Densetsu Satsujin Jiken in 2008.