Seiji as he appears in Jubaku no Machi.
|Name in Kanji||セイジ|
|Name in Romaji||Seiji|
|Fighting Style||Hokumon no Ken|
|Appearances||Jubaku no Machi, Shin Hokuto no Ken.|
Daisuke Kishio (young Seiji)
- Seiji (セイジ)
- Appearing in the novel Jubaku no Machi and its animated adaptation Shin Hokuto no Ken, Seiji was a renegade of the Hokumon temple, who had a love-hate relationship with his father Sanga for abandoning him in the wasteland while he was only a child. It was revealed that Seiji learned all the secrets of Hokumon no Ken in less than three years.
- Seiji travelled to Last Land to defeat his father and steal his power, only to find Kenshiro had already killed him. With Kenshiro having left the city to visit the Hokumon temple and retrieve medicine for Bista, Seiji took over Last Land, taking Sāra as his prisoner, and at one point, sexually assaulting her. It turned out she was the same girl he saved from a wild dog when they were children.
- Seiji finally fought with Kenshiro, but despite the ferocity of his fist, Kenshiro remarked that the ascetic nature of Hokumon no Ken made it inferior to the assassination style of Hokuto Shinken, and defeated him. Seiji then committed suicide by pressing the fatal point Heiketsushu (閉血愁) in his body to atone for his past crimes.