Gaku Shin Ten made his first appearance in Battle 201. At 18 years old, he is categorized as Dou and specializes in Katsujin Ken, formerly known as Satsujin Ken. His martial arts expertise lies in Chinese Kenpo, specifically Tài Jí Quán. As the leader of the Santoryu Team and its strongest member, Gaku harbors a deep-seated resentment towards Ma Kensei, declaring that "anything connected to the Ma family must be eradicated, even if it's just a cat." He seems familiar with Ma Renka and Ryuu Genson.
Gaku is characterized as cold, calculating, and heartless, viewing his teammates merely as pawns for manipulation. This attitude stems from an incident where his execution within the Black Tiger White Dragon clan was interrupted due to his defiance of the head's orders. None of his friends intervened to help him during this critical moment. This heartlessness is reflected in his demeanor, often depicted with wild eyes and a chilling smile. However, upon learning about the unwavering loyalty of his teammates, who vow never to abandon him again, he appears to develop a softer side towards them.
Initially, according to Kensei, Gaku despises the Phoenix Alliance because of its millennium-long conflict with the Black Tiger White Dragon Alliance. During his fight with Kenichi, it becomes evident that this hatred has more personal roots. It traces back to an event where Kensei saved Gaku from death, resulting in his demotion to the lowest rank within the Black Tiger White Dragon Alliance and preventing him from committing suicide.
