Years ago when kushina and her guard know as danko uzumaki came to Konaha instead of leaving he decided to stay and fell in love with an Uchiha konoichi and had their son ash the Uchiha didn't expect him because of his red hair and blue eyes he didn't look like Uchiha so the konoichi left the Uchiha compound to raise her son and be with her boyfriend.
Ash was left with kushina and Minato during infantcy and toddler years because in order to pay their rent they continued to do Ninja work so ash grew up around Naruto and was taught by his dad that Naruto was above even his own life as it was his mission to protect Naruto no matter what so at the age of 1.5 he started learning taijutsu and kenjutsu from his dad and shurikenjutsu and an little bit of genjutsu from his mom.
On the day of the nine tail outbreak danko uzumaki and Minato fought hard to retrieve Naruto and save kushina which ultimately ended in danko giving his life by blocking an genjutsu for Minato while being ran through by multiple kunai after the death of kushina and Minato in order to seal the nine tail they decided to split it between Naruto and ash.
After the heroic deaths of kushina and Minato Naruto became an orphan mikato could not adopt him for the Uchiha clan elders forbid it as he was not Uchiha but danko,s wife could for she had left the clan and Naruto lived with them for about 8 days before the Uchiha hate began as villagers suspect the Uchiha was behind the outbreak of the Ninetails because some Shinobi seen an sharringan in its eyes and the Uchiha planing an coup decided to kill danko,s wife and Take her sharringan because of her being from an purer bloodline of Uchiha samurai and as ash took Naruto for an walk in his stroller they struck as Uchiha elites took her life and and stole her eyes
After ash,s mother death he unlocked his sharringan and his first tomoe it was unique because of its white color After the murder hiruzen allowed ash to keep Naruto and the house as time passed ash watched over Naruto and 12 Years later the boys entered ninja school.