Dragon Ball has never been particularly known as a dark series by any means. Its action has always been larger than life and its threats were always precarious, but even then, Dragon Ball always managed to maintain its lighthearted spirit. However, there have been some points throughout the Dragon Ball franchise where all the positivity and optimism that Goku's personality would usually bring seemed entirely absent from the equation.
Source：https://www.cbr.com/dragon-ball-darkest-moments/
