Ren could develop a sense of loyalty towards Misaki. At first, he might be only interested in winning cardfights for his own glory. But when Misaki is in trouble or is being bullied by other cardfighters, Ren steps up to protect her. This loyalty could also translate into him being more selfless in their joint cardfights, sacrificing his own chances of victory sometimes to ensure Misaki's success, which in turn changes his overall character from a self - centered cardfighter to a more team - oriented one.
One possible plot could be that Ren and Misaki team up for a big cardfight tournament. They start off as reluctant partners but gradually learn to trust each other's strategies. As they progress through the tournament, they face tough opponents that force them to combine their unique skills. In the end, they not only become great friends but also reach the finals and give a tough fight to their opponents.
One possible storyline could be Kai and Misaki teaming up for a high - stakes cardfight tournament. They face various opponents and along the way, their friendship deepens as they learn more about each other's cardfight strategies and personal dreams.
One idea could be to focus on a new character who discovers a rare and powerful card that has been lost for ages. They then have to learn how to use it while facing off against more experienced players who want to take it from them.
For Kai, his development could involve him becoming more open - minded. In the fanfic, he could start to see the value in different cardfight styles other than his own through his interactions with Misaki. For example, if Misaki has a more creative and unorthodox style, Kai could learn to incorporate some of those elements into his own gameplay, which would also show his growth as a character.
There are often fanfics that explore the backstories of the cards themselves. In a 'Cardfight Vanguard' fanfic, the author might write about how a particular powerful card came into existence, like the story behind Blaster Blade's creation. This could involve some epic battles in a mythical realm and how the card's power was sealed within it.
One common theme is friendship. Since they are characters from the Cardfight Vanguard world, their bond as friends is often explored. Another theme could be support. They support each other in their cardfight endeavors in many fanfictions.
One interesting Naruto Cardfight Vanguard fanfiction could be one where Naruto uses his ninja skills to enhance his cardfight strategies. For example, he might use his shadow clone jutsu to create multiple 'avatars' in the cardfight, confusing his opponents. Another could be a story where the characters from Naruto are transported into the Cardfight Vanguard world and have to learn the rules of the game to get back home.
For Usui, he could develop from being the cool and carefree guy to a more responsible and mature person. His main focus would shift from just having fun with Misaki to taking care of her and their unborn baby. For example, he might start taking on more part - time jobs to save money for the baby's future.
Maybe the fanfiction could revolve around a mystery in the Cardfight Vanguard universe that only Ren and Asaka can solve. There could be a powerful and rare card that has gone missing. Ren, with his analytical mind, and Asaka, with her intuition, team up to track down the card. Along the way, they face off against various characters who might be involved in the disappearance, all while strengthening their partnership through cardfights.
A lot of 'Cardfight Vanguard Ren x Aichi' fanfics have the theme of rivalry. Their competitive nature towards each other is a big part. But this rivalry is often shown as something that ultimately strengthens their bond. Also, the theme of trust is common. They have to trust each other in cardfights and in life, and this is often a central aspect in these fanfics.