The protagonist of the series of the same name. He has mastered many of the world's fighting styles.
In ancient Japan, there was a shape shifting wizard known as Aku and he resurfaces and attacks the nation. When the emperor is captured, his son is sent to train throughout the world in many forms of discipline and combat. When he becomes an adult, he meets upwith his mother, who gives him the sacred sword which was efficient enough to defeat Aku. When the Jack returns home to face the wizard, he is sent through time into the distant future, where Aku still rules over a world filled with high technology, aliens, and other bizarreness that the samurai does not understand. Taking on the name Jack, the samurai makes a big name for himself as he struggles to free the future from Aku evil clutches, and he hopes that one day he can return to his own time to stop Aku before this future comes to pass.