Deep down in Naruto's mind scape laid a great and powerful demon. A being made completely of chakra. There was no need for the village to worry about it getting out since it was trapped there behind giant, thick red prison bars were it has been since Naruto's birth.
The fox woke from its nap and lifted its head.
"Hmm my jailer has received a gift," thought the fox.
He sensed the change in his container after the transplant. The boy now had a pair of eyes with untapped potential to gain byakugan and sharingan.
The fox glanced at the form of the unconscious boy. Curled up in a ball, outside of his cage, and away from his reach.
I shall enhance and upgrade those eyes so that my container will be powerful and will have no trouble defending himself. If he dies because of this stupid seal so can I. And I can't have my jailer looking weak in the face of my other siblings and their containers," thought the fox.
"I watched your fight with the human who took away your fight. You displayed very little skill and left yourself open to an attack. I will fix your incompetence," said Kyuubi knowing full well that the boy could not hear him.
"Your chakra coils are just now developing so I can make these changes possible. I will be able to implant it into your body using my chakra. Be grateful brat," said the Kyuubi.
With that in mind the fox got to work changing the boy's new eyes for the better. After everything was done the fox went back to sleep.