An Inch Of Infinity

In the near future the entire world is conquered by a group of people known as Royalties, or the Royals for short. They declared war on the planet. If you were not with them, you were against them. by the end of the 21st century the world was utter chaos and anyone who did not follow the laws to the letter were taken away by the Keepers. Part ninja, part spy, part soldier, the Keepers were brainwashed citizens raised from 8 months old to be able to apprehend anyone. Only 87% made it through training.
The population was cut into 6 groups, one for each block, each the size of a continent. Every other healthy child was marked at birth to become a Keeper. Children were often sent to other blocks to keep the population exactly even, but not always. Rebellions rose but were extinguished quickly, before they even really started. Eventually the only hope was a single underground rebellion until even that began to disappear.