Leagues are rankings that are based on your Rating.You earn Rating by winning Quick Fights and Bets and being promoted to the next Stage or League. The more rating you have the higher your place in League become. Note that there is a limit to the maximum rating that you can get on a certain Stage and Prestige Level.
All players are divided into groups of 50 inside one League. To get promoted to the next League, you need to be in the top places (top 7 if the group is full) by the end of the Round. One League Round lasts 48 hours.