Spoon Sakiware is a pseudonym used by the Japanese voice actor Kohsuke Toriumi for his work in adult content. Toriumi was born on May 16, 1973, in Chigasaki, Kanagawa, Japan. He is affiliated with the talent agency ARTSVISION.

Under his legal name, Toriumi has built an extensive career in anime, video games, and drama CDs. Some of his most notable and long-running roles include Kiba Inuzuka in the Naruto series, Hajime Saitou in the Hakuouki series, and Shunsuke Imaizumi in Yowamushi Pedal. He is also well known for his portrayals of Cecil Aijima in Utano☆Princesama, Mikazuki Munechika in Touken Ranbu, Guido Mista in JoJo's Bizarre Adventure: Golden Wind, and Gyokko in Demon Slayer: Kimetsu no Yaiba. He also voices the character Lǐn Xuě Yā in the Thunderbolt Fantasy puppet series.

Throughout his career, he has frequently collaborated with other prominent voice actors and worked across a wide range of genres, from action series like My Hero Academia to comedic roles such as the narrator in My Deer Friend Nokotan. The specific role of Yukio Sudō in Kuro to Kin no Akanai Kagi, which you mentioned, is not listed among his mainstream credits in the available search results.