
Quick answer — Masaki Nakanishi voices Ooyama in Ron Kamonohashi’s Forbidden Deductions Season 2, Mad Kaiser in 'Tis Time for "Torture," Princess.
Masaki Nakanishi voices Ooyama (Ron Kamonohashi’s Forbidden Deductions Season 2), Mad Kaiser ('Tis Time for "Torture," Princess).
Ooyama is voiced in Japanese by Masaki Nakanishi.