
Quick answer — Osamu Saka voices Seitarou Sakaki in Mobile Police Patlabor, Masaki Amamiya in Cardcaptor Sakura, Shinpu in Hellsing Ultimate and 10 more characters.
Osamu Saka voices Seitarou Sakaki (Mobile Police Patlabor), Masaki Amamiya (Cardcaptor Sakura), Shinpu (Hellsing Ultimate), Gohan Son (Dragon Ball Z), Nishikido (Go! Princess Precure), Kamata (Memories), Fukumen Bushi (Ninja Scroll), Eikokusha Gensui (Steamboy) and 5 more.
Seitarou Sakaki is voiced in Japanese by Osamu Saka.