Attention: I am posting this part now because I am having trouble deciding if I should write what happens in the three years before the flux collapses (No time will pass on the outside) let me know if you want me to write what happens inside and I will make it a chapter.
Chapter 1: Birth of Namikaze Naruto the second flash.
Umino Iruka watched in mute shock as his favoured student fought a far superior opponent while physically exhausted from hours of harsh training, his determination and willpower were amazing to behold and if fresh he could have beaten the Chuunin Instructor.
But he wasn't fresh; he started the fight tired, sour and even his monstrous Chakra stores depleted, when the final blow a strike with one of his recovered Giant Shuriken, the blow was a mortal one.
And Uzumaki Naruto lay in an ever expanding pool of his own blood while Mizuki leaned forwards his hands on his knees gasping for breath but with a sinister smirk on his twisted face.
"I will admit demon, you put up a half decent fight" it was followed by what would have been a harsh kick, a kick which did not hit soft human flesh but a hard ethereal clear barrier adorned with entire sets of complex seal like runes.
The clear wall of runes rose high into the sky and slowly descending inside of the wall was a being only known of in legend, wild white hair billowing as he plummeted.
It was the Shinigami, falling beside the white haired being was somebody they easily recognised and he didn't look happy before the duo reached the floor the barrier solidified into a dark dome of nothing but one complex seal.
Namikaze Minato kneeled next to his son inside of the huge dome the Shinigami had created thankful for the chance to meet and spend time with his son but also hating it for how it had come to happen.
To turned to the being that he had spent the past twelve years assisting par his contract with questioning eyes, the aforementioned being snorted as his eyes slowed harshly and all of Naruto's wounds healed.
"You have three years in this flux Namikaze; I trust it will be enough time for him to gather sufficient strength under your ... expert tutelage"