With the series on its last few episodes, we got a chance to ask a couple of questions to Gen Sato, the voice of Maru in Tengoku Daimakyo. With the series on its last few episodes, we got a chance to ask a couple of questions to Gen Sato, the voice of Maru in Tengoku Daimakyo. Though Sato is also the voice of Maru in Tengoku Daimakyo, a compelling character with a mysterious backstory that viewers still only have a faint idea of.