
Quick answer — Youichi Nishijima voices Kaoru Isawa in Kaiji - Against All Rules, Claude Weaver in Black Lagoon: The Second Barrage, Sakharov in Black Lagoon: The Second Barrage and 1 more characters.
Youichi Nishijima voices Kaoru Isawa (Kaiji - Against All Rules), Claude Weaver (Black Lagoon: The Second Barrage), Sakharov (Black Lagoon: The Second Barrage), Fritz Stanford (Black Lagoon).
Kaoru Isawa is voiced in Japanese by Youichi Nishijima.