
Quick answer — Takuya Nakashima voices Kyouji Shirahama in Sasaki and Miyano, Ketchum in Shangri-La Frontier, Susugashira in Sonny Boy and 9 more characters.
Takuya Nakashima voices Kyouji Shirahama (Sasaki and Miyano), Ketchum (Shangri-La Frontier), Susugashira (Sonny Boy), Victor (Reincarnated as a Sword), Dorshe (Helck), Gil (Kuma Kuma Kuma Bear), Moguo Iijima (Talentless Nana), Heishi C (Chillin’ in My 30s after Getting Fired from the Demon King’s Army) and 4 more.
Kyouji Shirahama is voiced in Japanese by Takuya Nakashima.