Masaki Terasoma is a veteran Japanese actor and voice actor, born on May 8, 1962, in Nishinomiya, Hyogo Prefecture, and raised in Osaka Prefecture. He is a graduate of the Toho Gakuen College of Drama and Music. His career began in 1984 as a stage actor with the Haiyuza Theatre Company, making his film debut in W's Tragedy the same year. While he provided the voice for Shadow Moon in the 1987 tokusatsu series Kamen Rider Black, voice acting was not his primary focus until 1999, when he left the theatre company to pursue it in earnest. Since 2003, he has been affiliated with the talent agency Mausu Promotion. His stage name is often written in the phonetic hiragana script (てらそままさき) to make it easier to read, though he continues to use the kanji spelling (寺杣昌紀) for non-voice acting roles.

Terasoma has built an extensive and varied career in anime, providing voices for a wide range of characters. He is known for roles such as Kiroranke in Golden Kamuy, Toshiki Miyamizu in the critically acclaimed film your name., Yūgo Tennōji in Steins;Gate 0, and Sōichirō Kuzuki in the Fate/stay night series. His filmography includes Lieutenant Victor in Irina: The Vampire Cosmonaut, Hoō Ban in Shinobi no Ittoki, Roderick in Log Horizon: Destruction of the Round Table, Ronin in Star Wars: Visions, and Kōichirō Mutō in Japan Sinks: 2020. He has also been a recurring presence in long-running franchises, voicing characters like Hidan in Naruto Shippūden, Caribou in One Piece, and Looker in the Pokémon anime.

In addition to anime, Terasoma has a significant and celebrated career in tokusatsu, particularly for his voice roles in the Kamen Rider franchise. Following his debut as Shadow Moon, he gained immense popularity as the voice of Kintaros, the Kansai-dialect-speaking Imagin, in Kamen Rider Den-O, a role he has reprised numerous times in films and subsequent series. His other tokusatsu credits include roles in various Super Sentai series, such as the voice of Kishiryu Tyramigo in Kishiryu Sentai Ryusoulger. He is also active in video games, with roles like Vossler York Azelas in Final Fantasy XII, Jubei in the BlazBlue series, and Thales in Fire Emblem: Three Houses. Furthermore, he is a prolific voice actor for foreign film dubbing, providing the Japanese voice for actors such as Kurt Russell, Michael Fassbender, and Viggo Mortensen.