
Quick answer — Nobuo Tanaka voices Petr Čapek in Monster, Shouhei Inagaki in Tomorrow's Joe, Shintarou Chaki in Detective Conan: The Last Wizard of the Century and 3 more characters.
Nobuo Tanaka voices Petr Čapek (Monster), Shouhei Inagaki (Tomorrow's Joe), Shintarou Chaki (Detective Conan: The Last Wizard of the Century), Soueki Senno (Hyouge Mono), Kazuki Doumoto (Detective Conan: Full Score of Fear), Jin Fukube (Martian Successor Nadesico).
Petr Čapek is voiced in Japanese by Nobuo Tanaka.