Both Sasuke and Itachi slowly stand up and activate the 'Senjutsu Seal' on their wrist.
The damage to their inner organs and external wounds swiftly regenerates with the help of nature energy. Other than a source of Senjutsu, the seal can also use the stored nature energy to accelerate their healing process.
Whoosh… swoosh…
Itachi's Susanoo opens its arms and throws multiple Yasaka Magatamas toward Kabuto while Sasuke's Susanoo nocks several arrows on its bow and aims them at Kabuto.
Fwoosh… swoosh…
Kabuto's snake eyes trace the movement of every explosive chakra bead and he jumps on the ceiling and dashes upside down while avoiding the explosion from them.
Itachi also controls the power of his attack to not demolish the entire hideout on top of them.
Swish… swish… swish…
Sasuke fires several giant chakra arrows toward Kabuto after calculating his trajectory with his Mangekyo Sharingan.
Bang… bang… bang…
The arrows pierce through the ceiling while Kabuto narrows and dodges them.
Hmm…
Sasuke's eyes narrow, and he switches his target from Kabuto's body to the snake appendage hanging out from his body.
Bang…
The arrow pierces through the head of the snake and pins Kabuto on the ceiling.
"Oh! I almost forgot I have something like this after being used to the human body for so long." Kabuto hangs upside down from the ceiling.
He liquefies his body to escape.
Shiing…
Suddenly, Itachi appears in front of him.
"Tsukiyomi!"
Blood leaks from Itachi's eyes as he casts his Mangekyo genjutsu on Itachi. Kabuto's body turns limp as soon as he makes contact with Itachi's eye.
"Did you get him?" Sasuke asks him with caution.
Fwoosh… Splash…
All of a sudden, Kabuto stabs his arm through Itachi's stomach, prompting the latter to puke blood out of his mouth. He pulls out his arm, splashing blood more blood in the process.
"NII-SANN!!" Sasuke yells in shock.
"Kuku… do you think I haven't studied your abilities and prepared countermeasures for them?" Kabuto licks his lips.
SWOOSH…
Caw… Caw… Caw…
Itachi's body explodes into several crows and disappears. He reappears beside Sasuke with his 'Crow Substitution Jutsu'.
"Nii-san, are you alright?" Sasuke asks him with worry.
"I am fine!" Itachi nods and glances at Kabuto.
"Hehe… you might be wondering how did I counter your so-called most powerful genjutsu?" Kabuto pulls an Edo Talisman from the mouth of the snake on his back.
"I see! No wonder I couldn't trap you in my Tsukiyomi for so long." Itachi glances at the talisman and understands Kabuto's methods.
"You have overwritten several personalities within your mind by using these special 'control talismans' of yours."
"Hehe… I hate smart people like you. Since it's harder to surprise them as they can see through others with a glance." Kabuto clicks his tongue.
"You are right! Orochimaru researched Edo-Tensei for several years. He even stole the Fuinjutsu records of the Uzumaki clan from the village to learn several of their techniques. The initial version of the 'Edo Tensei' created by the Second Hokage Tobirama Senju just summoned a mindless immortal puppet that follows only a single command. That was its limitation since the 'Edo Tensei' won't be able to perform complex actions.
Orochimaru-sama researched a method to restore 'Edo Tensei's personality or even rewrite a new personality for 'Edo Tensei'. After years of fumbling around, Orochimaru-sama found some knowledge about souls in the scrolls of the Uzumaki clan."
Hmm…
Sasuke's, and Itachi's interest is piqued by this information. They recover their chakra and stamina while listening to Kabuto's banter. Kabuto adjusts his glasses and continues.
"Knowledge is power and the Uzumaki clan members were aware of it since they researched several miscellaneous techniques from all over the world. Among their collection, there was a record of demons and soul reapers, the so-called Shinigami." Kabuto continues.
"It's a common belief that after a person's death, a soul reaper harvests the souls and then guides it to the pure land. However, how can a reaper harvest a soul and then send the soul to the afterlife at the same time?" Kabuto pauses and looks at the Uchiha duo, not minding their attempt at recovery.
"It's because a living being has two types of souls, a True Soul, and a secondary soul. The reaper harvests this secondary soul and sends the True Soul to the afterlife. Now, this secondary soul is further divided into seven souls, which are Body Soul, Life Soul, Spirit Soul, Mind Soul, Yin Soul, Yang Soul, and the Free Soul." Kabuto explains the names of the seven souls to the Uchiha duo.
"Now let me add something! Edo Tensei is a summoning jutsu. Just like other summoning jutsu, it also requires a summoning contract and a sacrifice to summon something over. But who is the contract bearer in Edo Tensei?" Kabuto glances at Itachi.
"Hmm… it's the Shinigami!" Sasuke answers him.
"Hehe… smart!" Kabuto's lips curl up.
"A summoning contract with a reaper is much, much harder to sign than a regular summoning animal. Not only are the terms of the contract unfair since it defies the laws of nature, even the cost or the sacrifice is brutal. A regular summoning contract requires blood and chakra to initiate. However, an Edo Tensei requires an additional ingredient, a living soul, to perform the summoning ritual." Kabuto adds.
"So, the Edo Tensei exchanges the soul of one person to summon another person." Sasuke enquires.
"Yes, but not quite exactly. When a person dies, a part of their secondary soul disperses into the world before a Shinigami's arrival. However, with the Edo Tensei, the Shinigami harvests almost the entire secondary soul of the sacrifice, excluding the free soul, which is the memories of an individual in this world. Usually, the Shinigami harvests three to four secondary souls, but with Edo Tensei, the Shinigami manages to harvest six souls. So, it's a win-win situation for him."
"What does it have to do with the personality of a dead individual?" Sasuke interrupts him.
"Kuku… impatient, aren't you? I am getting to that point. The Shinigami trades three to four secondary souls of an already dead person, with the six souls of a living sacrifice."
"Hmm… these secondary souls are responsible for the identity and personality of a living being." Itachi remarks.
"Exactly!" Kabuto points out.
"And the 'control talisman' has a Fuinjutsu seal to bind the secondary soul to the body, thus giving it a personality. The more the number of secondary souls bound, the closer is the Edo Tensei to their original form. Also, since it's a control talisman, I can suppress or erase the personality whenever I want by cutting the connection with the secondary soul. Kuku…" Kabuto laughs manically.
"I understand now. You sealed your secondary souls in these talismans. This not only fortifies the defense of your mind but can also overwrite any external influence, including genjutsu, by changing the command seals on your secondary souls." Itachi realizes Kabuto's method.
"Quite a smart method, isn't it?" Kabuto licks his lips.
"This is my insurance to escape the 'Eye of the Moon Plan' of Madara Uchiha."
-----
Back at the HQ,
Izuna, who was also paying a portion of his attention to their battle, shakes his head.
'This snake bastard is a madman. He has the balls of the steel If I have to say. The matters of souls are no joke. A slight mistake and his soul will obliterate from existence, barring him any chance of reincarnation. He is just lucky that he didn't just turn himself into a living vegetable. Nevertheless, he has fool's luck to not only survive but even complete his technique.
Still, what intrigues me more is the person who saved Kabuto's life. Back then, I thought he won't survive after witnessing his situation at the Ryuchi cave. And I don't think the Snake Sage possesses the skills to save him. Now I am interested in this third party, who is stirring the undercurrents from shadows.' Izuna rubs his chin.
'There is already Kaguya, Black Zetsu, Isshiki Otsutsuki, and now this unknown third person.'
Hmm…
"Oh, Minato-san is already on the battlefield. He is fighting against Grandpa's technique." Izuna's words snap Ayaka's and Kushina's attention to the battlefield. They watch in surprise as Minato destroys the giant meteorite with his new technique.
Sigh…
"This Minato never learns. He and his naming sense." Kushina shakes her head.
"I think it's a good name." Izuna chuckles.
"Not you too, Izuna!"
While Kushina and Ayaka are focused on Minato and Madara's battle. Izuna focuses a portion of his attention on the coastal battlefield.
'Looks like my wife is struggling against Obito's Rinnegan. Hmm… Naruto is already on his way. Looks like another interesting battle will unfold before us. This tripartite confrontation is getting more and more amusing. Now, even I am itching for some action.'
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Note:- These battles are happening at the same time. It's just that I am writing them separately and I don't want to mix them together to ruin the fun.