A/N:- It is just the ground work for future. I am writing the story with Boruto in mind as this part will fill the void between Naruto and Boruto. So, our new villain won't mess much. Most of you who disliked this part, hear me out.
Izuna will reach God-tier in future and he need a catalyst to do that. It's not like I can pull 'Six Paths Power' out of thin air and you guys will accept it happily. I will write everything step by step, his struggle to gain God-tier power and new enemies he will face during this journey. So, be patient with the story. Also, thanks for your support. (No more 'Nerfs' from here on.)
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Obito and Black Zetsu immediately escape from the situation.
Minato engages in a fight against the Nine-Tails. His chakra reserves are low from the previous fight. Nine Tails prepare another tailed beast ball to shoot at the village.
'Summoning Jutsu: Food Cart Destroyer Technique,'
Minato summons a giant toad on top of Nine tails and crushes it on the ground. Minato teleports to Kushina and newly born Naruto to check on them. Kushina clutches his hand and nods to him.
"Are you sure, Kushina? You have just given birth to Naruto. You are very weak now. Also, a powerful enemy kidnapped Izuna. The village is on the brink of destruction." Minato questions her.
"That's the more of a reason for me to seal Nine-tails. We have to save Izuna after that."
Kushina walks out of the secret room with baby Naruto in her arms.
'Adamantine Sealing Chains Barrier,'
Kushina incorporates the Adamantine Sealing chains in a barrier to restrain the Nine-tails.
"Minato, I will use the 'Four Symbols Seal' to reseal Nine-tails inside me."
Kushina had tears in her eyes as she tried to convince Minato.
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Meanwhile, in the sky of Konoha,
The cloaked man holds Izuna in his hands. He grabs the right hand of Izuna, the 'Sin Seal' turns visible to naked eyes. A similar seal appears on the cloaked man's left hand.
Small chains come out from his seal and enter inside the Izuna's seal.
Aah
Izuna yells in agony, his soul start to get ripped apart from his body. The cloaked man draws a transparent apparition out of Izuna's body.
"You will get out of your misery soon. Such dominant power is not meant for an insect-like you. Let this power return to its rightful master."
The chains around the Grimoire rattles. The cloaked man pulls Grimoire out from the separate space and inspects it.
"Hmm It is still incomplete. Only two eyes are present around the seal, the rest of them are still missing. It makes things more complicated. Guess I will collect the rest of them later. For now, these two are enough."
The cloaked man pulls the Grimoire as the chains around it snap.
ArghAah
Izuna wreaths in pain and struggle desperately. The Sin seal on Izuna's hand activates and tries to counter the chains of the cloaked man.
"Futile attempt!"
The cloaked figure suppresses the seal and gives the last push to rip apart the Grimoire. Izuna's consciousness fades away.
'No! I can't die like this. I haven't lived long enough.'
His desperate attempts for survival initiate a change in his Mangekyo Sharingan and evolve it further. The Silver sclera forms three inner rings around the star shape pattern of his Mangekyo.
Aah
Large amounts of chakra rile up in his body. The force from the sudden burst of Chakra pushes away the cloaked figure and forms a complete body Susanoo.
Many dark markings and totems erupt from the seal and cover the Susanoo. The katanas of Susanoo fumes with the dark chakra.
Slash
The Susanoo slashes the pair of katanas diagonally at the cloaked man. The cloaked man creates another barrier around himself to block the katanas, but the katanas slice through the barrier like a hot knife cutting through butter.
A large criss-cross slash mark appears on the cloaked man's chest. No blood spills from the wound, the darkness corrodes the wound. The impact of the attack pushes the cloaked man towards a nearby hill.
Izuna's Susanoo chase after the cloaked man. The cloaked man stands up slowly and cracks his neck.
"I never expected such a situation. This insect can use the powers of Grimoire subconsciously. Still, if that's his best bet, then I will end this soon."
The seal on the left land of the cloaked man shines brightly and covers his body in a warm yellow light. This light removes the corrosion from wounds and repels the dark chakra.
A floating Grimoire appears beside him and heals his injuries.
Roar
The corruption on Izuna's Susanoo spread even further and encase it in black color flames. Dark flames coats katanas and the Susanoo swing them at the cloaked man.
A large pale white barrier blocks the swing and repels the flames.
Boom
The shock waves from the impact of katanas blow away the nearby hill. A large narrow gorge appears in its place. The cloaked man shrugs off the attack and floats higher in the sky.
Wings sprout out behind Izuna's Susanoo, and he chases the cloaked man to clouds.
"It's over."
The cloaked man creates a large spear out of the pale light and aims it at Susanoo. The spears shoot at Izuna at a rapid speed. The Susanoo attempts to block the spear with the pair of katanas, but they snap in half because of the power of the spear.
The spear travels further and penetrates the Susanoo and stabs Izuna. Izuna pukes out a mouthful of blood. The 'Sin seal' absorbs the blood and shines brightly.
The two Sin eyes detach from the Grimoire and float in front of Izuna.
'Limbo Hengoku,'
Two Limbo shadows rip apart the dimensional barrier and float in front of Izuna. The Sin eyes shine brightly and attach to their chests.
Dark markings similar to Izuna appear on their body and cloak them in darkness.
RoarRoar
Both shadows roar violently and form Susanoo of their own. Their Susanoo is smaller than Izuna. One of the Limbo shadows forms a Scythe from the Chakra and the other Limbo form a large greatsword.
Both of them disappear and appear in front of the cloaked figure and attack him relentlessly.
"Oh! You can even summon Limbo Shadows from 'Border Prison Dimension'. But your power is still too weak."
The cloaked figure stretches out his right hand.
'Shinra Tensei,'
A large repulsive force pushes back the Limbo Shadows together with the Susanoo.
"You may be invulnerable to physical attacks and sealing because of the 'Sin eyes' but that doesn't mean you can change your nature."
Two clones of the cloaked figure appear beside him and engage in combat with 'Limbo Shadows'.
"In the end, they are still shadows and fears the light. Now let me take back, what I came for?"
The cloaked figure vanishes and appears in front of Izuna.
"Enough prancing around, it's time to sleep."
The cloaked figure coats his hand in strange white energy and grabs the last chain of Grimoire connected to Izuna's soul.
Aah
The intense pain wakes Izuna from his slumber. In a desperate attempt to preserve his life, Izuna claws his left hand on the seal of the cloaked figure.
Aah
The light burns Izuna's hands and the surrounding darkness disperses.
Hahahaha
"Your Grimoire of Sin is of Dark Nature, and my Grimoire of Virtue is of Light nature. They are polar opposite to each other. What are you trying to achieve other than bringing harm to yourself?"
Izuna continues to clutch tightly around the seal. The 'Virtue Seal' on the cloaked figure's hand activates and releases an enormous amount of Light Chakra.
Izuna frantically absorbs this Chakra and his Susanoo changes again. The right side of Susanoo turns black from the dark Chakra, and the left side turns white from the Light Chakra.
'Light-Darkness fusion: Cosmic Obliteration,'
The Susanoo compresses the stolen Light Chakra and Dark Chakra in a large volatile ball and throws it at the cloaked figure.
The cloaked figure is stunned at this drastic change.
"This, How is this possible? Impossible, How can you combine the light and darkness?"
Boom
The attack launches the cloaked figure towards space and explodes violently. The brightness from the explosion lights up the sky momentarily.
The Grimoire retracts back to the 'Sin seal'. The chains of the Grimoire have extensive damage to them. The Susanoo dissipates and Izuna's chakra reserves hit rock bottom.
Having drained the last bit of his Chakra, Izuna falls from the sky. His consciousness starts to fade. Izuna forces himself to stay awake and concentrate his mind on a space co-ordinate near Minato's location.
'Flying Thunder God,'
Izuna senses Minato's co-ordinates and teleports to him. They still have to deal with the rampaging Nine-tails.
'I don't want Minato and Kushina to needlessly sacrifice their life. I will protect them.'
Fwoosh
Izuna teleports from the sky and falls on the ground.
The large nine-tails wrapped in 'Adamantine Chains' appears in his vision.