The Kyuubi no Kitsune was the strongest of the demons. His nine tails stood as a testament not only to his power, but also to his age and knowledge. He was a god amongst demons. So his fury at being imprisoned in a human infant was understandable.

For years he raged against his prison. He clawed and bit at the seal, only to be repelled. He threw his massive form at the bars but they never budged, refusing to allow him the freedom he craved. He fought and he fought and he fought. All to no avail.

When his rage had quelled he began to ponder his imprisonment. He examined the seal which locked his cage, but was unable to pierce the tapestry that the Death God had woven. He debated the merits of channeling his chakra into the seal, the bars, or his host. But his chakra would not affect his prison, and it would simply leak out of his warden. He contemplated all this and more over the course of still more years.

After contemplating all possible theorems and concepts and avenues, he slept. He slept the dreamless sleep of demons, for they have no conscience to trouble them. No moral code embedded in their subconscious that makes lesser beings question their actions. Or rather, his sleep would have been dreamless. As quiet and undisturbed as it had ever been. But instead, he dreamed memories. As he slept, the mighty Kyuubi no Kitsune lived the life of his host.

He saw an infant who was refused the most basic of care. He saw a toddler who was left alone when he tumbled and injured himself. He saw a child who was attacked by civilians and shinobi both. He saw a boy who found a dream, a goal, a reason to press on. He saw a youth who forged within himself the dedication to see that dream achieved.

Then, he awoke. And he saw before him the subject of his dreams. He laughed when his jailer demanded a portion of his chakra, as rent of all things. He considered refusing. But he remembered the youth from his dreams, the one who stood before him now. Small, fragile, weak in comparison to him. He made his decision.

He was the Kyuubi no Kitsune. He was the strongest of the demons. He was akin to a god.

If he could no longer be the strongest, then his host would be.