After entering Naruto's body, that chakra
rapidly dispersed through every one of his chakra pathways.
It began assimilating Naruto's own chakra.
It was foreseeable that, in a few years, Naruto's chakra would be completely assimilated, and he would automatically gain a Sage Body.
However, Leon was clearly not satisfied.
"This is taking a little too long. Then I'll use Naruto to test the thing I just researched."
Leon clapped his hands, rose to his feet, and pressed a finger against Naruto's forehead.
He began making fine adjustments with his mind—
using the scattered Asura Chakra as a foundation to alter Naruto's genes.
Because chakra itself was the fusion of physical energy and spiritual energy.
Using chakra to affect genes was therefore as easy as pie.
Leon first spent a few seconds transforming Naruto into a Sage Body.
Then he began adding the things he had just researched.
Wood Release Kekkei Genkai, Yang Power, Otsutsuki Bloodline purification...
A few breaths later, Naruto had completely gained the same physique and bloodline as Asura from a thousand years ago.
And within the illusion.
Leon accompanied Naruto as he grew up, starting from the age of three.
From the Chunin Ninja Exams to the battle against Pain, then to the Infinite Tsukuyomi.
Every time he added an ability to Naruto's body,
he would simultaneously teach Naruto the techniques for using that ability within the illusion.
Besides that, he taught Naruto all the ninjutsu he had previously learned from the Book of Seals.
Though Naruto mostly failed to learn them.
In the end, when the Naruto in the illusion was utterly defeated by Kaguya Otsutsuki and watched helplessly as Leon was pierced through the chest and died.
The illusion ended there.
This was purely Leon's twisted sense of humor.
He liked this kind of dark,