Goku and Vegeta have become the iconic duo representing the Dragon Ball brand. Before becoming fierce rivals in their quest to protect Earth, both characters were once allies. Their first battle occurred during the Saiyan Saga and played a significant role in the subsequent character development.

In the Saiyan Saga, Vegeta is depicted as a character who plans to annihilate Earth, while Goku is the only one capable of standing against him. Despite Goku being overpowered, the Saiyan prince could not move due to the injuries he sustained. In a pivotal moment, Krillin had the chance to defeat Vegeta with Yajirobe’s sword but chose to spare him at Goku’s request.
Later, during the Majin Buu Saga, Vegeta feels a deep resentment because Goku had previously defeated him and continued to grow stronger. Therefore, he allows Babidi to control him through dark magic to regain his lost power. After achieving the desired strength, Vegeta challenges Goku again to prove himself.

Vegeta realizes that he has sacrificed his own will to Babidi’s control because he still harbors feelings of “humiliation” from Goku’s previous victories over him. From Vegeta’s perspective, it would have been better to die as a warrior rather than be saved by someone he considered inferior.
It turns out that Goku’s competitive spirit has ignited Vegeta’s resentment, leading him to transform into Majin Vegeta. Despite later acknowledging his mistakes, Vegeta’s pride drives him to showcase his strength against Goku. This battle is a testament to their intense rivalry and has become one of the most significant moments in the Dragon Ball series, showcasing the enduring bond and conflict between these two Saiyan warriors.