The year is 20XX. The ninja, who once forged the history of Oedo, were scattered across the country during the Meiji Restoration.
As ninjas mingled with other clans, their bloodline thinned, and they gradually faded from sight. The descendants of these ninja clans, seeking to preserve their heritage, formed the WNA (World Ninja Association) in the hope of carrying on their legacy.
And so it was that the WNA succeeded in developing Ninja-Gum, an art which could summon forth the strength of the Shinobi.
And yet creating the most powerful Ninja-Gum requires the strongest of ninja DNA.
So it was that the Ninjala Tournament was held, that the mightiest of all ninjas could be found...
A type of gum developed by the WNA to bring out the power of the Shinobi. It's an indispensable item at Ninjala tournaments.
It has one major side effect: any adult who eats it will be turned into a child. (Children are not known to suffer side effects of any kind.)