Zen Oh

Omni King Zen Oh (simply known as Zen Oh and known as Grand Zeno in the dub) is a character in Dragon Ball Super who originally made his debut as a minor character in the Universe 6 and Future Trunks arcs before becoming one of the two main antagonists of the Universal Survival Arc alongside his Future Counterpart. As his title suggests he is the ruler of the entire multiverse and holds authority over every god and mortal. He appears, sounds and behaves like a small child however despite this he rules the entire multiverse with an iron fist having been known to have erased 6 of what were originally 18 entire universes worth of innocent men,women and children just because he was angry at the time. Even other iron fisted ruling gods such as Beerus and Champa are terrified of him however despite this he is friends with series protagonist Goku.

Trivia

 * Although the tournament of power turned out to be a test of morality Zen Oh is the main antagonist because he was going to destroy all life had a selfish wish been made.
 * It's uncertain why he decided to hold a morality test despite the fact that his past actions weren't very moral to begin with. A possible theory may be that after becoming friends with Goku he is finally starting to care for mortal life.
 * Despite being friends with Goku Zen Oh can arguably be considered to be the overall main antagonist of Dragon Ball Super as a whole (or at least the first 131 episodes since the creators announced that they intend to continue the show and the last episode hinted that Zen Oh is starting to have a change of heart) due to the fact that not only did he hold the tournament of power but because his system of destruction and creation was what put the earth in danger during the Battle of Gods and Universe 6 arcs.