In addition, he is known for voicing rather tall or massive inhuman villains like Coyote Starrk in Bleach, Fukuro in Fairy Tail and Deep Sea King in One Punch Man.

He is the official dub-over artist of George Clooney, Kiefer Sutherland, Dwayne Johnson and Ma Dong-seok.

After graduation, he joined the Haiyuza Theatre Company and made his debut as an actor in Kamen Rider Black RX in 1989.

[5] Koyama made his debut as a voice actor in ER[5] and initially focused on dubbing, but since the 2000s he has also appeared in many anime and video games.

In anime, he plays many austere characters, but he covers the gamut from serious to gag, from good guys to cold-hearted villains, comical roles to dynamic ones, and from lustful characters like Kristofor in the game Infinite Undiscovery to the aloof and free-spirited role of Leonard in the Angelique series.