Old Grandmother had devised the rules of the "Gift":
"When an NPC's love for them becomes undying, an almost pathological urge to kill them will arise in that NPC's heart. The stronger the love, the stronger the killing intent."
"This killing intent will become a physiological phenomenon, just like eating, drinking, and relieving oneself. Alongside it will come abilities beyond the human realm."
"These abilities are born from a 'God's' praise and expectations, so they will be related to whatever was praised."
"The 'Gift' has five stages: latent, initial, stable, rational, and supreme..."
"Upon reaching the highest stage, a 'Gift bearer' can control their own emotions and wield their abilities freely."
On the surface, it looked as though Old Grandmother had forbidden them from becoming too intimate with NPCs because she opposed Yanbai's younger sister falling in love.
In truth, Old Grandmother knew that any NPC the children would break the rules to get close to was a special existence.
The current Black Zetsu, as well as Uchiha Itachi with his own ulterior motives, were both beneficiaries of the "Gift."
NPCs with humanity experienced joy, anger, sorrow, and happiness too. They were no different from complete souls.
Under these rules, a God's "Gift" was divine grace in which "blessing" and "curse" coexisted.
The power born from a "God's" praise was the blessing, while the urge to kill that God was the curse.
The intensity of that killing intent was how Old Grandmother assessed an NPC's value.
"So what does a 'supreme' Gift bearer represent?" Yanbai looked at Madara Uchiha in confusion.
Madara Uchiha shifted his gaze from the Red Spider Lily Sea to Yanbai. "The conversion into a special 'system' requires two people."
Yanbai was utterly puzzled by this.
"'Supreme' means their love for a God has reached its greatest