Ninja Revolution
In this world, Many centurys have passed since the days of Naruto. And life has changed, as life does. Things developed, modernized and left may traditions behind. Even the ninja of this world have dwindled, ninja training becoming more like teaching kendo in schools of japan. As such, the power behind the ninja has decreased. What used to be fire breathing human weapons in training have become less powerful and under trained. In fact, many of the teachers of today can be mesured as Genin and early Chuunin by the standards of the past.
 
Still, there are some who have clinged to the old ways, just as the kung fu masters and swordsmen we know, traditions are never completely dead. However, those as skilled as even a jonin of old are scarce and often hermits away from the main populace. Even the name Kage means little more than that of a mayor or other elected official.

The world is simply at peace. Vilages have become citys, nations now only as seperated as states, and the art of the ninja turned into sport, contests, and for military usage.