Goku is pretty much the star of DragonBall Z. He would sacrifice his life for the Universe to save it, such as what he did to stop Cell. He reaches all Super Saiyan transformations in DBZ first except SSJ2, his son Gohan achieved that level first. He is the most powerful, friendly, and pure hearted character in DBZ, but he never defeats anyone except Buu, after going SS3. DBGT has a dramatic ending of him leaving in the crowd. More to come soon...