NucleoENG

It is not limited to human beings, all souls have quality and quantity (of energy).
Quality aside, flora and fauna had souls of very little energy.
Compared to that, the amount in human souls was enormous.
Whether this much energy was in any and all humans was not yet confirmed.
Were they actually using this energy? It depended on their Skills, which used such Spirit Energy.
Data engraved on the soul, would become one with the soul’s bearer.
As for whether it was possible to input this data directly, it wasn’t so simple.
First of all, there’s the ego, which is enveloped by the Nucleic Heart.
It is there that all the data is engraved.
The crystallization of energy around the Nucleic Heart forms into the soul.
The Possession Jewel was a vessel on which this Heart was projected.
The Heart didn’t possess its own energy, but the ego did.
So it was possible to have an ego without necessarily having a strong enough soul to utilize Skills.
And the Possession Jewel is able to use the Spirit Energy as a substitute for one’s internal reserve of energy.
But that had its limits, considering that the quality of the energy being different.
Well, it was a simple toy for enjoying the Labyrinth so the limits didn’t matter.
The point is, even if the Nucleic Heart had Skill data engraved inside, without enough Spirit Energy, the Skills could not be used.