when naruto was 12 he once did a summoning justu before he had a contract, and was reversed summoned, but instead of going to Mount Myoboku like jiraya he went to earthland.
Here he met master makarov after a some time and explaining they made a deal in 12 years naruto would come back to earthland and join fairy tail after master makarov placed a time space magic on naruto to transport him back to him in 12 years, by then all his enemy's would have been dealt with and he would have saved/get his friend sasuke back from his hatred and become hokage.
Naruto went back to konoha like it al never hapend nowing that in 12 years he would go back there forever.
After the 4 ninja war having killed obito with the help of sasuke and his susano they could finaly deal a fatal blow to the ten tails and its controlers obito and madara uchiha killing them with no leader both black and white zetsu gave up and surrendered.
Naruto was quickly appointed to be hokage by the age of 20 a large party was held for the new hokage by all of the nations.
Naruto was a hero in all of the nations known everywhere as the strongest and fastest person alive, after 2 years the kage decided that naruto would be appointed supreme-kage and lead the entire elemental nation with his title.
the last 2 years went by fast nothing happened that was interesting.
sasuke became his bodyguard and sakura became his assistant and they got married.
"sakura would you get me the reports of all the missions from last week." said naruto "sure thing naruto-sama." sakura answered
"drop the " sama " sakura makes me feel old." making sakura and sasuke laugh out loud "sakura you now you're behind on work so if you like unpaid overtime be my guest and sasuke your wife here would not mind if i where to go to a strip club and since your my bodyguard you cant leave my side until i am home."
sakura and sasuke's faces dropped to the floor thinking that he was really good in mental torture after his training with the anbu then sakura left the room getting the papers he asked for sasuke "i need to talk to you." said naruto "why is it important." asked sasuke "yeah its important Naruto answered, im leaving." said Naruto Sasuke not believing what he heard said "are you for real." "yes." Naruto said with a smile
"your not joking like any other time are you." said Sasuke "no im not joking im leaving in 2 days." Naruto said "don't say a word to Sakura she would beat me up for even saying this." "yeah..." said Sasuke in understanding.
"no one is supposed to now until im gone im going to send letters to every kage about that i will miss them and that they should not tell anyone about me leaving i told them to say i died of a heart attack i will be buried right there and then ok sasuke."
Sasuke agreed to do this for his best friend "i have made a goodbye letter just in case i really died before the day after tomorrow."
The scam of how he died was perfect, he would walk through the village and suddenly fall down then Sasuke emerge next to him and take him away later that day he told everyone Naruto had died from a heart attack and will be buried tomorrow it was a sentimental day in the elemental nations a friend died, a hero died, and a kage died.
From that day forward a mage was born Naruto walked to a massive door bearing the emblem of fairy tail and entered.