Whis is a major character in Dragon Ball Super, though you never really see him fight anybody.
We first think he is merely the attendant of Lord Beerus, the God of Destruction. Which is technically true.
Turns out he’s not only just stronger than Beerus, he was his teacher in fighting. Instead of being a god, he’s technically an angel.
Both of them spend most of the series, just eating food from Bulma.
He does train Goku and Vegeta to be stronger.
He’s not the strongest character in the series. His sister Vados apparently is stronger, and definitely his father the Grand Minister.
I did think it was funny, that he and all his siblings were exempt from being erased during the tournament of power. But since they’re all children of the Grand Minister who might be the real mastermind instead of Grand Zeno, it makes sense.
At the end of the series, he uses magic power to bring Frieza back to life without the use of the Dragon Balls.