Some pairings will be painfully obvious but for the rest I will try to be sneaky.
Tsuni Uchiha's hand was currently in the process of being broken. His wife Sumura Uzumaki was having a baby. This would be nice if the NINE TAILED FOX HIMSELF WASN'T ATTACKING THE VILLAGE." Luckily the head and body was out and she just had the legs to go. "Cmon baby push you got this." THIS ISN'T EASY YOU KNOW" she squeezed his hand harder. He could swear he felt a snap in his hand anymore pressure would end his shinobi career. Seriously the nine tails was looking like the better option here. After another five minutes the baby was born. His eyes were closed and he wasn't crying. As the doctors were about to hit him and make him cry. The baby opened his eyes revealing two sharingan eyes with one tomoe in each. Everyone was shocked but then suddenly a man appeared in a yellow flash.
A few minutes earlier.
Minato Namikaze 4th Hokage of the village hidden in the leaves had just defeated the masked man. He believed he was Madara Uchiha but that is totally different news. He was about to teleport to Kushina and Naruto to carry out his plan when he felt a presence. It was coming from Konaha hospital so he decided to check it out. He teleported to the hospital via the marker placed there.
Present time
Minato arrived at the hospital and started running through the halls as quicky as possible. Even kunai jumping which is just him throwing then teleporting to the same kunai over and over again. He then appeared in a yellow flash in a room. He looked around and he saw his long time friend, a nurse, and a baby with the sharingan. Seems normal he thought wait WHAT THE FUCK. Sure enough a baby with the sharingan was laying there staring at him seemingly. He then had an idea and after a brief talk with Tsuni it was decided. He took baby Alex in his arms and was off to the races.
Timeskip Kushina has got nine tails in chakra chains and Alex and Naruto are on a ceremonial throne
I will take him with me said Kushina. "No I won't allow it said Minato." DON'T YOU SEE MINATO I'M GOING TO DIE ANYWAYS." Yes but for the village I'm going to seal the nine tails into these two children." Minato your not a jinchuriki you can't unless you." You wouldn't" said Kushina yes I will and I am"said Minato. "My only regret is that Naruto won't have a parent." Exactly thats why you have to." She didn't get to finish her sentence as Minato looked at her with a firm gaze the gaze that meant he made up his mind. "Fine I will assist you with all I have left." Thank you Kushina." He summons the reaper and seals half in Naruto and half in Alex. Minato and Kushina give the last of their respective chakra into both seals. Then they both collapse dead content with their lives and sacrifices. Later the third and a group of ninja would arrive on the scene to see two babies crying.
Welp thats the end of my first ever chapter in the fanfiction business now their may be a few questions. No Alex will not be OP out the gate just stronger than kids his age. He will be like Itachi basically. I will add a new kekkai genkai for another character but don't worry it won't be OP. As for Alex becoming a jinjuriki it is for him to have more potential and cuz I felt like it. Like I said he won't be OP out the gate but he will be good friends with the nine tails early. Btw the chapters will get longer as the story progresses. Anyways if they're any more questions you have review and I will try to answer bye.