Toshihiko Seki, born on June 11, 1962, in Sendai, Miyagi Prefecture, Japan, is a celebrated Japanese voice actor, actor, singer, and narrator. He has been active in the entertainment industry since 1983 and is affiliated with 81 Produce, a prominent talent agency.

Seki is known for his versatility, often voicing characters with serious or easily agitated personalities, such as Duo Maxwell in Mobile Suit Gundam Wing, Iruka Umino in Naruto, Kaien Shiba in Bleach and Riki in Ai no Kusabi. He has also portrayed deranged villains like Legato Bluesummers in Trigun and Muzan Kibutsuji in Demon Slayer: Kimetsu no Yaiba. One of his most iconic roles is Momotaros in Kamen Rider Den-O, a character he has reprised in numerous productions.

In addition to his work in anime, Seki has contributed to video games, movies, and dubbing. His talent and dedication have earned him recognition, including being ranked as the 9th favorite voice actor in the 26th Annual Reader's Poll by Animage Magazine in 2004.