The one element of the Dragon Ball that fans can always expect to encounter is Saiyans. Besides the fact that the manga’s main protagonist, Goku, is a Saiyan, there are more than 15 other Saiyans including Vegeta, Raditz, Bardock, Kale, Caulifa, and Goku’s sons Gohan and Goten, who all play important roles in the manga’s progression. With so many Saiyans involved in the story and their inherently competitive nature, the question becomes: who among them is the most powerful Saiyan of all time?
Any discussion of the most powerful Saiyan must include Broly. As a child Broly’s power level was so high that many believed him to be the incarnation of the “Legendary Super Saiyan,” a Saiyan of otherworldly abilities who appears once every thousand years. For fear that he would one day become too powerful to control, King Vegeta exiles Broly and his father from the Saiyans' home planet Vegeta forever. King Vegeta’s decision is not wrong because Broly goes on to prove those childhood rumors about him correct. For most of his life, Broly’s power is restrained by his father, however, once his father dies, Broly becomes unhinged, allowing his powers to grow to their full potential. His power reaches near-invincible levels when he transforms into his Super Saiyan form. The problem with Broly, however, is that the more powerful he gets, the more uncontrollable he becomes. This results in wasted energy and a lack of focus that an experienced opponent could use to overcome Broly’s unmatched power.
There is probably no Saiyan more confident that he is the most powerful member of the species than Vegeta. The onetime heir to the throne of the Saiyan home world, Vegeta was raised by his father King Vegeta to be the most powerful Saiyan, then forced by Frieza to sharpen his skills to a fine edge. As one of Frieza's top warriors, Vegeta gains valuable fighting experience taking part in the countless wars and battles that Frieza wages across the universe. However, it is only after his encounter with Goku that his abilities really begin to level up. This is largely due to his prideful inability to accept that a common Saiyan like Goku could be more powerful than Saiyan royalty. That desire to be better than Goku has led Vegeta to achieve power levels no other Saiyan has achieved except for Goku. Indeed, Vegeta’s Ultra Ego form is potentially more powerful than any form Goku has, but it is also incredibly dangerous for Vegeta since it requires him to be hit by an opponent in order to become stronger.
While Goku is seen as the safest choice in picking the most powerful Saiyan, it is also the correct choice. Sure, while Goku cannot compare with Broly’s pure power levels, or Vegeta’s battle experience, neither can compare with Goku’s competitive spirit and goal to be the most powerful fighter in existence. As a result of that desire, Goku is constantly seeking tougher, more intense, challenges. The advantage of this for Goku is the fact that stress forces Saiyans to transform. The more intense the stress experienced, the more amazing abilities the transformation brings.
As a result of the intense stress, Goku has undergone and continues to put himself through, he has achieved transformations few Saiyans have achieved. This is most recently illustrated by the super-powerful Ultra Instinct form. While Goku has yet to fully master Ultra Instinct, the fact that he is the only Saiyan to have attained it proves why he is currently the most powerful Saiyan of all time in the Dragon Ball multiverse. Moreover, knowing Goku’s mentality, fans can bet he’ll put the work in to master the form like no other Saiyan can.