Akira Toriyama's Dragon Ball is a franchise that has undergone a lot of change and evolution from its early days, when it followed a young Goku and Bulma as they travelled the world. In Dragon Ball Z, Goku's son Gohan was introduced, and in various instances, was developed as the one fighter capable of surpassing Goku. This culminated in Gohan becoming the central figure in the defeat of Cell; a battle which also claimed Goku's life.