- Name (romaji): Seto Koji
- Nickname: Setomaru
- Profession: Actor and Singer
- Birthdate: May 18, 1988
- Birthplace: Fukuoka, Japan
- Height: 175cm
- Weight: 52 kg
- Star sign: Taurus
- Blood type: A
Mengawali debut dengan bergabung menjadi
D Boys dan grub band
TETRA FANG sebagai vocalist. Kemudian mengawali akting menjadi pemain
Kamen Rider Kiva (2008) dan terpilih menjadi pemain pendatang terbaik. ^_*
- Sadako 3D (2012) as Ando Takanori
- Moshidora (2011) as Asano Keiichiro
- Runway☆Beat (2011) as Mizorogi "Beat" Biito
- Kamen Rider × Kamen Rider Double & Decade: Movie War 2010 as Kurenai Wataru
- Ju-On - Black Girl (2009) as Tetsuya
- Kamen Rider Kiva: King of the Castle in the Demon World (2008) as Kurenai Wataru
- Shakariki (2008) with cameo appearance
- Kamen Rider Den-O & Kiva: Climax Deka (2008) as Kurenai Wataru
- Tenshi ga Kureta Mono(2007) as Hayama Izamu
- Tonari no Yaoi-chan as Tibe-kun (2007)
- Hit Parade as Tiger's member (2006)
- Teen Court as Saburo Takada (NTV, 2012)
- Kurumi no Heya as Mitamura Kentaro (NHK, 2011)
- Yotsuba Jinja Ura Kagyo Shitsuren Hoken~Kokuraseya as Kinoshita Sho (YTV, 2011, ep 10)
- Gou as Mori Ranmaru (NHK, 2011)
- Nasake no Onna as Akagawa Tomoya (TV Asahi, 2010)
- Tumbling as Takenaka Yuta (TBS, 2010)
- Rinne no Ame as Mikami Shuhei (Fuji TV, 2010)
- Otomen as Yamato Ariake (Fuji TV, 2009)
- Atashinchi no Danshi as Okura Satoru (Fuji TV, 2009)
- Kamen Rider Decade guest starring as Kurenai Wataru (TV Asahi, 2009, ep1,31)
- Koizora as Sakurai "Hiro" Hiroki (TBS, 2008)
- Kamen Rider Kiva as Kurenai Wataru / Kamen Rider Kiva (TV Asahi, 2008)
- Abarenbo Mama as Abe Naoya (Fuji TV, 2007)
- Happy Boys as Segawa Kyoichi (TV Tokyo, 2007)
- Rocket Boys as Kanno Makoto (TV Tokyo, 2006)
