
Quick answer — Rintarou Nishi voices Freddie Saturn in Space Brothers, Moblit Berner in Attack on Titan: No Regrets, Raizou Todoroki in Ace of the Diamond and 19 more characters.
Rintarou Nishi voices Freddie Saturn (Space Brothers), Moblit Berner (Attack on Titan: No Regrets), Raizou Todoroki (Ace of the Diamond), Shuichi Matsumoto (Initial D 4th Stage), Jiguro (Moribito: Guardian of the Spirit), Mashira (Vampire Hunter D: Bloodlust), Charlie (Fullmetal Alchemist: Brotherhood OVA Collection), Kokuryuu Matsuoka (ID: INVADED) and 14 more.
Freddie Saturn is voiced in Japanese by Rintarou Nishi.