Shape-shifting Naruto

Long ago, the Tailed Beasts were made. They were the apex predators, the protectors of the Shinobi world. Humans and taild beasts lived together, protecting one another. That changed, however, when selfish shinobi wanted the tailed beasts for their power.

Years later, one 5 year old boy found an injured puppy sized black and red fox. The boy carefully cooed to the fox and picked it up, taking it home. The boy treated the fox's wounds, and in return, the fox showed the boy its true form. The fox turned into a nine tailed fox.

As a show of kindness, the fox sealed itself in the boy. No one, not a single person, found out.

That boy is Naruto Uzumaki.