The Reincarnation Mirror was a secret treasure for Soji's alternate identity, Mizuki Ember.
Especially now that his true body had traveled to a future Parallel Universe, the only way to keep Mizuki Ember's identity moving was for the Reincarnation Mirror to channel Chakra into this body.
Soji had once believed that after obtaining the Reincarnation Mirror, he would never have to worry about running out of Chakra again.
Yet this time, Soji once again experienced the agony of not having enough Chakra.
It was not that the Reincarnation Mirror could no longer provide Soji with Chakra. Rather, Mizuki Ember's Chakra output was simply disproportionate to the Reincarnation Mirror's Chakra input!
It was just like the Impure World Reincarnation Jutsu.
Strictly speaking, the claim that reincarnated undead possessed infinite Chakra was actually wrong!
It was merely that the Chakra recovery speed of reincarnated undead was truly astonishing.
For example, in most situations, after a reincarnated undead expended one unit of Chakra, it could recover five units per second.
That was why so many people mistakenly believed that the undead summoned by the Impure World Reincarnation Jutsu appeared to possess infinite Chakra.
In other words, reincarnated undead merely recovered Chakra quickly; they did not have infinite Chakra!
The reincarnated Third Hokage in the original work had explained this exact situation.
After continuously using powerful ninjutsu at high intensity, his Chakra consumption surpassed his recovery speed. For a short while afterward, he was unable to use ninjutsu.
Because his Chakra had not yet recovered!
Of course, this situation rarely occurred for most reincarnated undead.
Thus, it was not entirely wrong to say that over ninety-nine percent of reincarnated undead possessed infinite Chakra.
Naturally, if a small number of reincarnated undead recklessly maintained high-intensity Chakra output, they would end up like the reincarnated Third