The plot proceeded like in the anime, even with help of Sarutobi Hiruzen the conclusion of the battle stays the same, at best they just managed to delay the Nine-Tailed fox slightly.
Minato joined the suppression of Kyuubi after he managed to find Kushina lying on the ground motionless beside Naruto.
Before making his way back to the village, a black figure intercepted him which he assumed was Uchiha Madara, it greatly delayed him, but fortunately, he managed to sever the connection of Kyuubi during the battle using a contract seal.
-*Author's note* I decided to slightly modify how Obito unsealed the Kyuubi to make my Fan-fic from being too similar to the Original, lest the readers say, I'm lazing around, In the Original Obito had a brief confrontation with Minato before he managed to kidnap Kushina and unseal the Kyuubi.-
Many villagers died in the process including Iruka's parents were tragically killed.
In the final moments Minato appeared with his son and wife, Minato decides to sacrificed himself to seal the Kyuubi using Naruto's body.
Furious about the idea of being sealed again, The Kyuubi decided to attack Naruto, to protect their child, Kushina and Minato used their body to bear the brunt of Kyuubi's attack, because of it they are hanging in the thread of life and death.
"It's time for Eight Trigram Seal, I want to put some of my chakra into Naruto as well." Tiredness was apparent in his voice.
Looking at her son, Kushina caressed his face one last time.
"Take a bath every day, and stay warm. Find friend just a few that you can really trust! so don't feel down, if you're not good at something, Respect your teachers and seniors at the Academy, Make sure to save the money you make from missions, Don't drink alcohol until you're twenty, I'm a woman myself, so I don't know much about this, but there are only men and women in this world, speaking of vices, watch out for Jiraiya-sensei, ya know! Believe in yourself, Believe in your dreams! There are many things I want to share with you, I wish I could stay with you longer!" Kushina uttered her last words at his son with tears in her eyes.
"Is everything your chatty mother just said," Minato said with a smile before his vision was engulfed in darkness.
Seeing that Minato and Kushina's unconscious body, Kaen decided to act swiftly, He was not a liar to say that he was not feeling anything slightly, he truly felt a hint of sympathy to the scene he managed to witness early.
After heading near to their body, Kaen's temple ached suddenly, information was quickly filling his brain directly.
After reading his new memories, he was stupefied, the memories entailed the new abilities his body had.
He can directly summon the white vortex that transported him here, he can now go to the purple space back again.
He also found in the memories that he can change the environment and time flow in the Purple Space to anything he wants, but it was also directly related to his strength.
After reading it's another function he can't help but smile warily, It really has great timing.
After breaking out into his own thoughts, he quickly used a syringe to get his objectives.
"They are truly fast" He muttered to himself.
He didn't deactivate his Byakugan for a second so he managed to spot running figures kilometers away from his directions.
He touched Minato and Kushina directly and they vanished, looking one last time at the protagonist who has a seal drawn in his body, he left quickly using his planned escape routes.
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In the place where the Kyuubi was last spotted, after Sarutobi and the other ninjas arrived they expected to see Minato and Kushina's corpse.
But they are confused when they only manage to find their son's body with a seal on it, Besides his body, a lot of scattered ashes can be seen.
Their eyes that were filled with confusion quickly cleared after realizing what happened based on the clues in the scene.
"We're too late." Sarutobi's face was filled with sadness.
The others just kept their silence, their faces were filled with sorrow for the disaster that their village had just undergone through.
Some of them lost their family in the process, The Fourth Hokage sacrificed himself for the sake of their village he was a Hero.
"Collect the remains of Hokage and Kushina, Bring their son to the hospital, we will hold their ceremony." He ordered them.
"Yes, Lord!"
They quickly collected the scattered ashes carefully.
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-Kaen' House-
Kaen was sitting on the ground, he was currently examining the purple space inside his body where Naruto's parents are.
Their bodies were floating in the purple space covered with whitish light, It was healing their body slowly.
Due to their grave injuries, he estimated that it will take at least a decade, but he guessed that the stronger he is the faster the healing process will be.
He decided to save them for several reasons, First, he is not a ruthless villain that will neglect others, If he has the ability to help those who crossed his path he will do so, but he is not a fool who will help here and there seeking them foolishly, if they crossed his path then they are linked by fate but if not, then he got nothing to do with it.
He is not a selfless saint to do so, In fact, good people in his past life died earlier than others for some unknown reasons.
Second, he tried to know if he can store living things directly, it succeeded as a result.
Third, It was an Indirect Compensation for their blood.
And Lastly, He was moved by their heroic spirit, If he was in their place he was not so sure if he can do the same too, He is a selfish person by nature.
After exiting his trance-like state, he quickly touched the black marble in his pockets.
Two bottles of blood quickly manifested in front of him, seeing his hard-earned reward a smile couldn't help but escape in his face.
He risked being found out just to obtain them, If his plan failed then his previous effort will be wasted.
They will not just kick him out to their village, They will surely hunt him down and put a bounty on his head.
But now seeing his efforts being rewarded, he was relieved, now he will truly be a peerless genius surpassing even Uchiha Itachi and Senju Hashirama!
Namikaze Clan is known for being good in all aspects, they are knowing for possessing tremendous talent in space and ninjutsu.
Like Uzumaki Clan, they are wiped out because of their monstrous potential.
As for Uzumaki Clan, they are popular due to their high affinity for seals, every one of them contains tremendous vitality and chakra, They are the pioneer in terms of sealing techniques, Their physique was also one of the best.
Feeling their threat possessed, The Four Great Villages decided to unite against them.
Now imagine combining their bloodline in one body? a body that contains Tremendous Chakra and Vitality, Stronger Physique, High Affinity to Space and Seals, Not mentioning his already talented body, he was a monster among monsters, a dragon amongst men!