Tatsuya Hayama, better known by his ring name DOUKI, is a Japanese professional wrestler signed to New Japan Pro-Wrestling (NJPW), where he is a member of the House of Torture, having joined the group in 2025. He was previously part of Suzuki-gun from 2019 until its disbandment in 2022, then joined Just 5 Guys in early 2023, which was later changed to Just 4 Guys before his departure in 2025. He is a two-time IWGP Junior Heavyweight Champion and a one-time IWGP Junior Heavyweight Tag Team Champion with fellow House of Torture member SHO.