Krillin gets off to a slow start in Dragon Ball Super. While he's present for the first two arcs, he isn't given much to do, and the Universe 6 and Future Trunks Sagas do even less with him.
If you weren’t aware of Super Saiyan 4’s origin in Dragon Ball Daima, the finale reveals that Goku was able to achieve the level through off-screen training. While he first debuted the transformation ...