One would assume that Goku’s legacy would be one of universal heroism, given the fact that he’s defeated villains like Frieza, Majin Buu, and Moro (all of whom posed an intergalactic threat), though they would wrong, as Goku’s final villain confirms that his Dragon Ball legacy is, in fact, a quite shameful one.
When Goku got his start at the beginning of classic Dragon Ball, he was just a kid with an optimistic mind, a spirit for adventure, and a desire to become the greatest martial artist in the world. While helping his friend, Bulma, find Dragon Balls, Goku got in a lot of personal training, as nearly every town/village/city they traveled to was plagued with some kind of looming villain who was exploiting the people there. Before long, Goku wiped out the vast majority of earthbound evildoers, only to move on to the cosmic evildoers in Dragon Ball Z–and that’s where he tangled with the real world-enders like the evil Saiyans, Frieza, and Majin Buu. Then, in Dragon Ball Super, those threats were elevated even more, with the same being said for the final era in the Dragon Ball franchise (chronologically speaking), Dragon Ball GT. However, it was within GT that Goku learned all his heroism was utterly overshadowed by another, less heroic, aspect of his character.
Goku’s Dragon Ball Legacy is That of a Fool, & the Dragon Balls Confirm It
In Dragon Ball GT episode 57 (written by Atsushi Maekawa, directed by Osamu Kasai, produced by Toei Animation), Goku is fighting one of the last Shadow Dragons that escaped the cracked Dragon Balls: the Three-Star Shadow Dragon. Earlier in the series, it was explained that every wish Shenron granted also created a corresponding flux of negative energy, and that energy gave birth to a Shadow Dragon. When the dark energy built up too much, the Dragon Balls cracked, and one Shadow Dragon was able to emerge from each of the Dragon Balls. Given that they are the manifestation of the energy created by the Dragon Balls’ magic, it’s almost as though the Shadow Dragons are an extension of the Dragon Balls themselves, which means that they know everything the Dragon Balls would know if the orbs were sentient (which, they kind of are). In other words, the Shadow Dragons already knew all about Goku and his many adventures throughout the series–and with all that information, they came to one conclusion: he is a fool.
The Three-Star Shadow Dragon (who is an extension of Dragon Ball’s final villain, Omega Shenron), calls Goku a fool in this episode specifically because Goku believes him when he says that he won’t cause any more trouble if Goku just lets him go. In true Goku fashion, he decides to trust the villain, which leads to the Shadow Dragon attacking Goku before the Saiyan is forced to kill him on the spot. This is a pattern of Goku’s that has plagued him from the start. Goku believed Raditz when he said he’d be good, and that cost him his life. Goku gave Frieza another chance to turn over a new leaf, and that nearly cost him his life. Goku even gave Cell a senzu bean to give him a fair chance against Super Saiyan 2 Gohan. These actions are undoubtedly foolish, and they usually end with catastrophic results that have to be corrected by the Dragon Balls when the villain is finally defeated–which is why the Shadow Dragon knows exactly how foolish Goku really is, he’s been cleaning up his messes for decades.
In essence, the Dragon Balls have been judging Goku his entire life, and this Shadow Dragon revealed what the seemingly eternal orbs actually think of him: that he’s a fool–a shameful Dragon Ball legacy that totally overshadows all the good Goku’s done across every era of the franchise.