Dokugakuji is a fictional character in the manga and anime Saiyuki, the bodyguard of Kougaiji. In the Saiyuki Reload and Reload Gunlock animes.
He is the older half-brother of Sha Gojyo, and was previously known as Sha Jien, and Gojyo has been searching for him for years. In the manga (original Saiyuki), the two first meet in book three. Unlike his brother, Dokugaku is a full youkai, the son of their father's legal wife (whereas Gojyo was the son of their father's human mistress). In the manga Sha Jien would often calm his mother's violent outbursts towards Gojyo by sleeping with her, acting as a replacement for his dead father. When his mother finally snapped and attempted to murder Gojyo Sha Jien killed her in order to save his brother.
Dokugakuji is now a loyal servant of the youkai prince Kougaiji, son of the Ox-Demon Gyumaoh whose revival the Sanzou Ikkou are trying to prevent. Dokugaku stumbled into Houtou castle one day roughly six years before the beginning of the manga, and was hired without question by the trusting prince. To quote the manga "I decided I owed you my all."
His weapon of choice is a sword which he summons in the same way Goku does his nyoi-bo, or Gojyo his shakujou. He usually fights Gojyo when the two groups meet.
(Source: Saiyuki Wikia)