Supreme Kai of Time, who from now on I'll be calling Time Kai to save a few hours of typing, is the ruler of Toki Toki City, and the Time Nest that it is home to. She is the overseer of the flow of time in the universe, correcting mistakes and stopping time travelers from causing temporal disturbances.
Despite her odd sense of humor, and unimpressive stature, Time Kai is nearly as powerful as she is important. She has shown the ability to heal, grant resistance to powerful godly magic, manipulate time, and cook up poisons potent enough to kill the mightiest of warriors. In fact, millions of years ago, she was able to seal a powerful magic user, Demigra, in a dimension outside of time, known as the time crack.
Despite her childish appearance, Time Kai is likely the oldest living Kai. She is able to extend her life and youth by living in Toki Toki City permanently, as time does not pass within the city. Because of this, it seems that she is functionally immortal, and thus able to oversee time for as long as it exists. Despite this, it is said that if the Time Nest were to be destroyed, time itself would cease and the universe would be all but destroyed.
Time Kai is, to put it lightly, less than sensitive to the feelings of others. After bringing Future Trunks to the Time Nest for the first time, she lied to him and told him his altering of the Dragon Ball timeline was a sinful act that could only be forgiven with years of service to her. After this, her and Trunks formed the Time Patrol, which basically serves to do Time Kai's job for her. Despite this sounding like a rather bitchy thing to do, it is implied that Time Kai didn't know Trunks would be hurt so much by her actions, as she had not had much practice in social situations before meeting Trunks.
Time Kai received her position by raising Tokitoki, a bird that can manipulate and create time, to adulthood, and becoming friends with it. Tokitoki is a large part of the reason that the city and Time Nest function as they do, and has even more power over time than the Kai who raised him. He is pictured here, petting a weird ass owl.
There's a golden statue of Hercule Satan in Toki Toki City, which is great, because now I don't even have to write a joke for him.
Fact: Supreme Kai of Time is the best Kai.
