Well, Naruto is obviously one of the main characters. His friends like Shikamaru, Choji, and Sakura also often appear. Since it's about his happy childhood, Iruka Sensei is usually a key character too. They all play important roles in creating the happy and adventurous scenarios that are typical of this kind of fanfiction.
There might be a 'Naruto Happy Kid Fanfiction' where Naruto forms a special club with his friends when he was a kid. They could have their own unique missions like finding the best ramen in the village or making a super cool treehouse. In these stories, we get to see the lighter, more carefree Naruto before all the big challenges he faces as he grows up. It's all about his simple joys and friendships as a kid.
Perhaps the kid is from a foreign land that Naruto visited during one of his missions. The kid could be an outcast in his own place because of some unique trait. Naruto, being the kind - hearted person he is, decides to adopt him. It could be that the kid has a different kind of chakra or a strange mark on his body that makes others afraid of him, but Naruto doesn't care.
One reason could be to protect his friends. Naruto doesn't want his friends to worry about him, so he pretends to be happy even when he's facing difficulties. For example, when dealing with the threats from powerful enemies, he shows a happy face to keep his team's morale up.
Happy Naruto fanfiction usually features a lot of celebration and joyous events. For instance, there could be a grand festival in Konoha to celebrate Naruto's birthday or an anniversary of peace. The story might also include Naruto using his skills in a non - combat, fun way, such as using his shadow clones to perform a big show for the village kids. The overall atmosphere is light - hearted, with little to no dark or tragic elements.
Well, if Naruto got the Rinnegan as a kid in fanfiction, it would completely rewrite the story. He'd have an edge in combat right from the start. With the Rinnegan, he could see chakra in more detail, which would make his learning of new jutsu easier. His opponents would be caught off - guard by his sudden access to such a powerful dojutsu. This could lead to some interesting plot twists, like him being able to solve problems in the village or against other ninja villages more quickly and efficiently.
Yes, there might be such a fanfiction out there. The idea of crossing over different fictional universes like Naruto's and Kid Flash's can lead to some really interesting and creative fan - made stories. It could explore how Naruto, with his ninja skills and determination, would react to the super - speed and powers of Kid Flash. Maybe he'd be in awe or try to learn from him in some way.
It's possible that the kid is a result of some sort of time - travel or alternate reality situation. Maybe the kid is actually Naruto from a different timeline or dimension, and Naruto has to figure out how to deal with this strange situation while on his training trip.