Fusion Zamasu had proved to be too powerful for Goku,Vegeta and Trunks combined despite all their efforts.Having no other choice Goku and Vegeta use the Potara Fusion to win becoming Vegeto once e battle goes in Vegeto's favor.During the conflict Vegeto accidently damaged the Time Ring sending Goku and Vegeta back all the way to the beginning of Saiyan Saga and changes occur