As Dragon Ball Super established, the Kais are Gods of Creation, but each of the Dragon Ball Multiverse worlds also has a God of Destruction to balance it out. For Universe 7 -- where Dragon Ball's iconic protagonists call home -- the God of Destruction is Beerus, always accompanied by his angelic attendant Whis.
While Beerus has firmly maintained his title for eons, Dragon Ball Super revealed that mortal warriors -- like Universe 11's Jiren and Toppo -- are identified as potential successors, eventually training to replace the various Gods of Destruction. With Dragon Ball Super's introduction of a canonical version of the Legendary Super Saiyan Broly, could he be Beerus' heir apparent?
In between traveling the cosmos, destroying planets and enjoying the best gourmet food Universe 7 has to offer, Beerus is searching for an opponent worthy enough to spar against. Beerus initially believed Frieza to be that potential match but is eventually intrigued by a prophetic dream about the legendary Super Saiyan God -- leading him to seek Goku and Vegeta.
Beerus is ultimately impressed and has Whis train the Saiyan duo to further hone their combat skills and raw power. He even grows visibly nervous after seeing the new power levels that Goku achieves throughout Dragon Ball Super, from Super Saiyan Blue Kaio-Ken to mastering the Ultra Instinct transformation. However, the canonical anime film Dragon Ball Super: Broly introduced perhaps the strongest Super Saiyan of them all in Broly.
The previous non-canonical Broly was a Legendary Super Saiyan that cut a path of destruction through Universe 7's southern galaxy before Goku and the Z Fighters defeated him as he targeted their native northern galaxy. In contrast, the canonical Broly is a much more sympathetic character. He's prone to losing control of his power and anger while still maintaining his innocence from growing up on the remote planet of Vampa. Socially withdrawn, Broly is shown to be protective of his friends and even strikes up a tentative friendship with Goku by the end of the anime film rather than the deep-seated hatred towards him that defined the non-canonical Broly.
Despite this more sympathetic nature, Broly is visibly capable of immense amounts of destruction, completely obliterating a glacier and exposing the Earth's molten core in his battle against the Z Fighters. Broly is one of the most powerful warriors in the entire Dragon Ball franchise, able to fight Super Saiyan Blue Gogeta. The prospect of Broly honing his abilities, gaining mastery over his rage and power -- perhaps under the tutelage of Whis -- is frightening. That potential could undoubtedly make him the worthy opponent Beerus has been searching for. What's more, Broly could become Universe 7's God of Destruction in a way that Goku or Vegeta never could.
Broly's sympathetic nature doesn't make him incapable of becoming a God of Destruction though he may be less cavalier in rampaging across the cosmos as Beerus has become. Adept at laying entire planets to waste without slowing down, Broly is one of the most overwhelming opponents Goku and Vegeta have ever faced. Beerus has not expressed any interest in surrendering his position as God of Destruction any time soon but is interested in finding another fighter worthy of his attention. Broly might be that promised opponent, and, with Beerus eons-old already, he may have just discovered his replacement if he decides to move forward on divine retirement.