Dragon Ball Z-2
This is the world of Dragon Ball, a world of science, magic, aliens, and martial arts heroes. In this world, Son Goku and the Z Warriors, save the world time and again from those threats that seek to rule and destroy through fear and power.
This world has seen the defeat of Frieza, the bio-android Cell, and the terrifying Majin Buu. There are probably more threats hiding in the woodworks, but these warriors stand ready to fend them off!
This world is almost identical to the main Dragon Ball canon, with one small but crucial difference.
This side story is less about those heroes, but more about Raditz, the Saiyan whose arrival on Earth once upon a time heralded the threat of Vegeta and Nappa. Having died at the hands of his brother, Raditz was sent to Hell in the Afterlife, where his tale was thought to have ended. Little did he know that there was more to his fate than he would have imagined.
Upon entry into the Multiverse, some years after the defeat of Majin Buu, Raditz found himself mysteriously returned to the land of the living. Despite not knowing the reason, Raditz took this second chance to make the most of his new life. He took to the Multiverse with glee, fighting monsters and villains and heroes alike, for the thrill of the fight just as any other Saiyan. After a little bit of convincing from his brother, Goku, he decided to fight for the Union, because surely there would be strong people to fight on the other side.
Several years later, Raditz fought the Vegeta of another universe, the Immortal Prince of All Saiyans, challenging him for rule of the Saiyan race. The battle was hard fought, but Raditz defeated the immortal prince against all odds. Before he realized it, he was saddled with the responsibility of the Saiyan race, as well the rule of Earth-4555 (See Also: Dragon Ball Z-3).
Raditz has since relinquished rule of the planet to the rightful king, though he remains the King of All Saiyans, intent on restoring honor to his race. Only time will tell if he succeeds.