
Quick answer — Jirou Saitou voices Denken in Frieren: Beyond Journey’s End, Hatou no Nioo in ONE PIECE FAN LETTER, Eadric in Vinland Saga Season 2 and 21 more characters.
Jirou Saitou voices Denken (Frieren: Beyond Journey’s End), Hatou no Nioo (ONE PIECE FAN LETTER), Eadric (Vinland Saga Season 2), Olaf (Vinland Saga), Wallace (PLUTO), Eitaro Shidou (Cross Game), Wyman Wilker (SPY x FAMILY Season 2), Jinnosuke Mudou (The Quintessential Quintuplets Movie) and 16 more.
Denken is voiced in Japanese by Jirou Saitou.