"What's the matter, Grandma?" Tsunade follows Mito.

"Tsunade… this kid, Yuji Kura, is not normal. He is… he is similar to me." Mito points towards the seal on her stomach.

"What?" Tsunade's eyes widen in shock.

"Yuji is a jinchuruki!"

"Not exactly, but it's similar. Being a host for the Nine-tail beast for such a long time, I came to share a portion of its powers. This power allows me to sense negative emotions hidden within the heart of a human. And this kid…" Mito glances at Yuji.

"… there is a lot of bloodlust, fear, resentment, emptiness, loneliness, and other negative emotions within his heart. So, to pry further, I attempted to inspect his mental space. Tsunade, you are aware that the mental space of a person is the reflection of their soul and heart."

"Mm…" Tsunade nods at Mito's statement.

"Within this kid's mental space what welcomed me was the pitch black darkness, a darkness blacker than the black, a gloom so bone-chilling that it eats away the consciousness, a rage so fiery that it burns away the soul, a resentment so heavy that it drowns all hope, and an emptiness and loneliness so detached that even the entire world can't fill it."

Mito explains the feeling which assaulted her in Yuji's mindscape.

"Isn't that too exaggerated?" Tsunade stares at her old grandma's aghast figure.

"No words aren't enough to describe what I just saw," Mito recalls the appearance of a pitch-black demonic figure chained within Yuji's mindscape.

"A powerful youkai is sealed within this boy's body. If his emotions grow unstable, then the seal in his mindscape will break and the demon will be free from his fetters. It will wreak havoc in the shinobi world." Mito responds in a fearful tone.

"So, what should I do?" Tsunade asks Mito for advice.

"There are only two options. The first one is to kill the boy. With his death, the demon sealed within him will also perish. The demon will revive itself within a few centuries, but that's enough time to search for a solution."

Tsunade turns to the sleeping Yuji.

"He is a friend of Kushina and Nawaki. If possible, I wouldn't prefer such a solution. Is there an alternative method?"

"There is… but just like the first method, you wouldn't like it." Mito shakes her head.

"What's the method? If it's not extreme like killing the boy, then it's worth a try." Tsunade argues.

"This second method will solve the problem from the root, but just like the first method, the boy will lose his life," Mito explains.

"Tsunade, you must have heard about the sealing artifact of the Uzumaki clan?" Mito enquires.

"Hmm… I do! I heard it from father, but I never had an opportunity to take a look at it." Tsunade shakes her head.

"The sealing artifact of the Uzumaki clan, "Kutsūno Hako" also called the 'Box of Ultimate Agony' is a very powerful sealing artifact from the era before the Sage of Six Paths. This box has been passed down through generations of the Uzumaki clan as an heirloom. It was first discovered by the founder of the Uzumaki clan, Kenshiro Uzumaki, in an ancient ruin. Since then, this powerful relic has served a vital role in the fulfillment of duties of the Uzumaki clan."

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"Duties of the Uzumaki clan?" Tsunade is astounded to hear this.

"Yes, since the foundation of the Uzumaki clan, the clan had a vital role to play in this world. The Uzumaki clan seals malevolent demons and youkai wreaking havoc within the shinobi world. This was an important task assigned to us by our founder." Mito explains the duties of the Uzumaki clan.

"We sealed these vile and evil demons and Youkais within the Box of Ultimate Agony, where they serve an eternity in imprisonment!"

"What if someone destroys the relic and releases all those demons sealed within its confines?" Tsunade asks in curiosity.

"That's impossible!" Mito shakes her head.

"The Box of Ultimate Agony is indestructible, both from outside and inside. No amount of power or physical strength can even scratch the surface of the Box of the Ultimate Agony. It's the reason this box serves as a prison for those malevolent demons and youkai."

"So, grandma… you mean… you wish to seal Yuji inside the box of ultimate agony?" Tsunade asks with a wry expression.

"That's what I thought initially, but…" Mito stares at Tsunade's wry expression.

"… looks like that's out of the question."

"There must be another way to prevent the demon from emerging. There must be one…" Tsunade stares at the seal on Mito's stomach.

Mito notices Tsunade's gaze and shakes her head.

"Tsunade, there is an inherent difference between the demons, youkai, and the tailed beasts. Demons are intelligent foreign entities from another world. Their sole purpose is to wreak havoc in the shinobi world and lay waste to its foundation. They won't spare any effort to doom this world. It's the reason these demons are sealed away in the Box of the Ultimate Agony. Similarly, most Youkais are born from malevolent emotions like hatred, anger, bloodlust, and other such negative emotions. Most youkai are mindless creatures who act on their instincts. Most of the time, these instincts are violent and thus such evil youkai harm people around them.

There are also good-natured youkais born from the positive emotions of the people. These youkais aid the surrounding people. Such youkais serve as the guardian deity of a place and a shrine is erected to honor them. The Uzumaki clan has contracts with multiple such youkais.

As for the tailed beasts, they are more like the incarnation of the force of nature. Tailed beasts are sentient chakra born from the vast nature energy spreads within the shinobi world. As such, these tailed beasts are much closer to the world than any other species. In the distant past, the tailed beasts aided humanity in the subjugation of the demons and the evil youkais. However, after a while, humans came to fear the immense power of the tailed beasts. They began formulating various methods to control such an immense amount of power, since tailed beasts are the very definition of power. After most demons and youkais were sealed or defeated, the tailed beasts lost their purpose. Contradiction and war spread among the humans and thus these humans turned to tailed beasts to subdue their power.

This act of betrayal from the humans enraged the tailed beasts. So, the tailed beasts used their immense power to wreak havoc among the human who attempted to control them. As such, the members of the Uzumaki clan had to step forward and seal them in human vessels to subdue their rampage. Since tailed beasts are a part of nature, sealing them inside the box of ultimate agony will harm nature. So, it's the reason we jinchurukis with special chakra were born." Mito explains the history of the demons, youkais, and the tailed beasts to Tsunade.

"Oba-san, then the demon sealed within Yuji-kun…"

"It's a foreign demon from another world." Mito states.

"There must be another way to subdue the demon sealed within Yuji-kun. He is just an innocent kid. Why does he have to bear such responsibility?" Tsunade bites her lips.

Sigh…

Mito sighs as she reminisces about some memories.

"You remind me of your grandfather. He was also naïve, like you."

Ah…

Tsunade turns silent and looks away.

"But it's that naivety that I liked about him the most. It allowed him to have an impossible dream and a drive to make those dreams a reality. Very well…"

Mito turns towards Yuji.

"That demon is still dormant within Yuji-kun's body due to the effects of the seal. He can still live a normal life without any worries."

"That's a relief to hear. I don't want this innocent kid to suffer such an injustice."

"It's too soon to celebrate. The demon might be dormant for now. However, any powerful emotional trauma might wake it up." Mito's expression turns serious.

"TSUNADE!! PROMISE ME… WHEN THAT DAY COMES… YOU WILL END HIS LIFE WITH YOUR OWN HANDS." Mito demands with an absolute tone, with no room for denial.

"This… I… I…"

"I will only accept a yes for an answer. If not, then I will seal this boy right away. I am still a princess of the Uzumaki clan and I must fulfill my role." Mito threatens her.

"I… Alright, I promise you. When that day comes, I will kill him with my own hands." Tsunade grits her teeth and clenches her fists.

'I… I am sorry, Nawaki, Kushina!'

"Good! I hope you will remember this promise." Mito nods at Tsunade's resolve.

"Nee-san, Grandma! We are back."

Nawaki, Kushina, and Minto re-enter the Uzumaki clan compounds.