Whis is regarded by some as the strongest fighter in the Dragon Ball universe, though there’s some question of whether or not he truly deserves that title. After all, he’s far from the only character in the world of Dragon Ball who possesses a divine power level.
Dragon Ball Super spoke volumes about Whis’ physical capabilities when it was revealed that he was the one who trained Beerus. By the God of Destruction’s own admission, Whis is much stronger than he is. This revelation made it abundantly clear that Universe 7’s assigned Angel is truly a force to be reckoned with, and a character that Goku and Vegeta may never be able to catch up to in the anime. While Goku is arguably strong enough to challenge Beerus now, he nor Vegeta have ever come close to testing Whis in their sparring sessions. Even the Legendary Super Saiyan himself couldn’t lay a hand on Whis in Dragon Ball Super: Broly.
Whis being more powerful than both Broly and Beerus confirms he’s the strongest being in Universe 7, but it doesn’t mean that he outclasses everyone in Dragon Ball’s multiverse. Aside from Zeno (who can erase anything in the multiverse but is not a fighter by any means), there’s at least one more character who is confirmed to be on a higher power level than Whis. He told Goku in a Dragon Ball Super episode that his strength is inferior to the Grand Priest, who is the father of all 12 known Angels. Goku desperately wanted to see the Grand Priest in action, but Whis strongly cautioned Goku against challenging him.
Whether or not there are any other fighters out there who can beat Whis was left ambiguous. According to Whis, the Grand Priest is one of the five strongest fighters across all 12 universes. What he didn’t mention was who the other four were, or if Whis counts himself as one of them. If not, there may be four more beings in the multiverse who can beat Whis in combat. Since Beerus is near the level of the other Gods of Destruction, it’s unlikely that Whis would rank any of them above him, but some of the Angels could be comparable – if not stronger – than him.
A character who has been described as Whis’ equal is Champa’s Angel, Vados. During the Universe 6 Saga, the character noted that she was once proven to be stronger than Whis, but as the latter pointed out, this was a long time ago. Whis explained that they’re most likely on an equal playing field now, although it’s hard to say for sure which one of them is right. But either way, there’s no denying that the number of characters capable of posing a real threat to Whis in Dragon Ball Super is severely limited. Whis is one Dragon Ball fighter who may never lose a fight on-screen.