Quick answer — Seiji Sasaki voices Oniwakamaru in Samurai Champloo, Tomoyuki Shinoda in Hajime no Ippo: The Fighting! - Mashiba vs Kimura, Atsuro Kawai in Initial D 4th Stage and 7 more characters.
Seiji Sasaki voices Oniwakamaru (Samurai Champloo), Tomoyuki Shinoda (Hajime no Ippo: The Fighting! - Mashiba vs Kimura), Atsuro Kawai (Initial D 4th Stage), Blueno (One Piece Film: Red), Harris (Squid Girl), Reiji Kageyama (Inazuma Eleven: Saikyou Gundan Ogre Shuurai), Sig Curtis (Fullmetal Alchemist: The Movie - Conqueror of Shamballa), Ayamaro (Samurai 7) and 2 more.
Oniwakamaru is voiced in Japanese by Seiji Sasaki.
