The story of Dragon Ball Z Kai follows Goku and his friends as they defend the Earth from various powerful threats. It includes battles against villains like Frieza, Cell, and Majin Buu. Goku, a Saiyan, constantly trains to become stronger and uses his martial arts skills and special abilities like the Kamehameha wave.
There's also 'Dragon Soul's Awakening'. In this fanfic, the Dragon Soul concept from Dragon Ball Z is introduced to the Naruto world in a really interesting way. It's a shorter read but packs a punch with its action scenes. The author does a good job of making the two different universes blend together, like how the chakra in Naruto can be related to the ki in Dragon Ball Z.
The main characters are Goku, a Saiyan who is the hero of the story. Vegeta, another Saiyan who starts as an enemy but later becomes an ally. Gohan, Goku's son. Piccolo, a Namekian. Krillin, Goku's best friend. And Bulma, who is important for inventing things that help the characters in their battles.
One interesting Dragon Ball Z Kai fan fic could be one that focuses on an alternate timeline where Goku never hit his head as a baby. This would change his personality and the entire course of the story. Another could be a story centered around Vegeta's training in a new, uncharted planet, exploring his growth without the constant presence of Goku. There are also fan fics that might explore the backstories of minor characters like Yamcha or Krillin in more depth, which can be really fascinating.
The popularity comes from the combination of two very popular and iconic anime universes. Fans of Naruto love to see how their favorite characters would fare in the high - energy world of Dragon Ball Z, and vice versa. The Dragon Soul aspect adds an extra layer of mystery and power that fans enjoy exploring.
There are fanfictions that focus on their family life. For example, a story might explore how Vegeta adjusts to being a father while still maintaining his Saiyan warrior pride. He might struggle with balancing training and spending time with his family, but Bulma is always there to keep him in check.
Vegeta could also work well. Vegeta's pride and determination, along with his powerful fighting skills, would contrast nicely with the Supreme Kai's more reserved and wise nature. They could learn from each other and have some intense rivalries within the story.
There are no such inappropriate 'Straight Shota' stories in the official Dragon Ball Z canon. Dragon Ball Z mainly focuses on epic battles, power-ups, and the adventures of Goku and his friends to protect the Earth from various villains.