Toshihiko Seki

In Demon Slayer: Kimetsu no Yaiba, produced by the studio Ufotable, Seki gives the Japanese voice to Muzan Kibutsuji, the progenitor of all demons and the central villain whom the Demon Slayer Corps seeks to destroy. The role fits a long-established line in Seki's career of portraying menacing, deranged antagonists. Over the years he has voiced figures such as Legato Bluesummers, Rau Le Creuset, Embryo, and Il Dottore, and Muzan ranks among the most prominent of these villainous turns.

Working since 1983, Seki has built a reputation for characters who are intensely serious or quick-tempered, including Duo Maxwell in Mobile Suit Gundam Wing, Iruka Umino in Naruto, Kaien Shiba in Bleach, and Genjo Sanzo in Saiyuki. His most famous part is the Imagin Momotaros from Kamen Rider Den-O, a role he has returned to across numerous later productions. In 2023 he headlined as the voice of the title character in Pluto, adding another leading credit to an already extensive body of work.

Seki's standing among Japanese voice actors has been formally acknowledged by fans and industry observers alike. In June 2004 he placed ninth among favorite voice actors in the 26th Annual Reader's Poll of Animage magazine, recognition tied largely to his performance as Rau Le Creuset in Mobile Suit Gundam SEED. In August 2007 Anime News Network counted him among the more prolific male voice actors, citing 215 credited roles at that time.