
Quick answer — Ryoukan Koyanagi voices Séverin Bientôt in Saga of Tanya the Evil, Ottarl in Is It Wrong to Try to Pick Up Girls in a Dungeon?, Kharga Klarus in Arifureta: From Commonplace to World's Strongest Season 2 and 1 more characters.
Ryoukan Koyanagi voices Séverin Bientôt (Saga of Tanya the Evil), Ottarl (Is It Wrong to Try to Pick Up Girls in a Dungeon?), Kharga Klarus (Arifureta: From Commonplace to World's Strongest Season 2), Takeshi Kido (Killing Bites).
Séverin Bientôt is voiced in Japanese by Ryoukan Koyanagi.