Zetsu knows that the merchant before him comes from the family he has been looking for. The same family Zetsu entrusted the plant all those years ago.
The family who can awaken Kaguya Otsutsuki if his original plan does not come into fruition.
The Haruno family is his failsafe. The one that will prove to be useful in the future when the time is right for Kaguya's resurrection.
They are the merchant family whose sign denotes a white circle, which was originally an Ouroboros symbol of resurrection or rebirth. The image of a snake eating its own tail which the family has changed into a Full Circle to hide the secret that most do not understand, except for a prophecy of a Goddess returning from their bloodline.
"Does your family still have the plant?" Zetsu asks in a rasping voice.
"Yes, Master Zetsu," The head of the Haruno family says. "We are keeping it safe and well-cared for as you have instructed us."
"Excellent. Make certain that your family takes care of it for many, many years or there will be consequences if something happens to it. So I ask that you tend to the plant like your life depends on it." Zetsu tells the man, who nods in acquiescence.
For a moment, there is complete silence and he notes the way the merchant in front of him hesitates before asking him a question.
"Master Zetsu, this plant has been with us for many generations but my ancestors have not properly explained to me the reason behind it, other than the prophecy of a Goddess. May I ask why exactly have you chosen our family to care for this magical plant?"
Zetsu knew the question was coming, considering that the true history of the plant has been watered down since many generations have passed and the oral history has diminished all throughout those years.
Hence, he sighs inwardly and says to the merchant.
"I chose your family because of your blood line. Many, many years ago, your family comes from a Shinobi Clan called the Torii Clan who has a bloodline limit that is able to pierce through the shroud of another dimension and summon powerful beings through a circular gateway. However, due to the Torii Clan's bloodline limit, your ancestors were hunted down and slaughtered. Now, the only surviving members are those with diluted blood, but your family still has their uses. In the future, your family will have the honor of resurrecting a Goddess through the plant under your care. Thus, your family must take care of the plant until I am ready to call upon your family. So heed my instructions and your family will be rewarded in the future. Fortunately, I have no worries about your family betraying me and this secret, considering that your entire bloodline is under oath that will prevent them from speaking this to anyone."
"Thank you for enlightening me on this matter, Master Zetsu," the man says.
Afterward, Zetsu watches as the head of the Haruno family submits to his will and passes down the knowledge of the plant unto the coming generations.
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A Hundred Years Later….
"What shall we do, Kizashi?" Mebuku Haruno says fearful as she gazes down at the two year old baby on the crib, who has just ingested something earlier that made the Haruno couple become terrified for their lives.
"We should keep this silent and pretend that we still have the plant," Kizashi tells his wife, whose face remains pale and frightened after the two had caught sight of their daughter swallowing the plant entrusted to them by a terrifying creature.
"We better hope that creature doesn't come knocking at our door anytime soon or our entire family is done for," Mebuki remarks as she brushes her daughter's hair.
For an entire minute, Kisashi doesn't say anything else.
"Shall we run and hide?" Mebuki suddenly asks. The note of fear is still clear in her voice.
"No, I don't believe so. Master Zetsu has chosen the Haruno family for a reason. Perhaps we still have a chance of surviving his wrath after he finds out what our daughter has done to his precious plant."
"And if Master Zetsu is not as forgiving with us? What shall we do then?"
Kizashi falls silent again before finally saying, "From what the prophecy says, it is supposed to resurrect a Goddess. Let's hope that this accident is beneficial to us and gives us a powerful daughter who might be able to combat that creature."
"But that's just wishful thinking, love! And if she does, how can Sakura fight that creature, when she is not even three years old yet?!"
"Master Zetsu has usually been making an appearance to the Heads of the family. So I am certain that he won't be paying us a visit soon until I die or Sakura becomes ready to take the mantle as the Head of the Haruno family. I am sure Master Zetsu won't find out about what happened until many years later. So let's hope that Sakura has attained some kind of power from the plant. If she does, we will either train her ourselves to become strong or have someone train her until she is ready."
"Let's hope so dear or we will end up in a casket if he finds out this early."
.
.
.
Meanwhile, Zetsu has taken liberties of keeping tabs on the family at a distance. So of course he knows what happened to the plant.
In fact, one of his clones was the one that shredded the plant into smithereens and had the baby eat it with his help.
After experimenting and meddling with the Haruno bloodline, the baby was the perfect match as Kaguya's vessel.
So he hadn't hesitated at all by letting the baby eat bits of the plant's leaves in order to activate her dormant genes.
Now, Zetsu will just have to assure the Haruno family that he was not out for blood.
And everything will become full circle in the coming years when Sakura Haruno becomes old enough to learn how to summon firsthand.