One popular 'kaidou x aren fanfiction' story could be about their adventures together in a fictional world. They might face challenges and overcome them as a team, with their unique personalities shining through in the narrative.
There are also some Tumblr blogs dedicated to fanfic sharing. You can search for tags related to 'kaidou haru x ren' on Tumblr. Some fans might post their own works or reblog interesting fanfics they've found. However, the search might take a bit more effort as Tumblr's search function isn't always the most precise, but it's still worth a try.
Another plot could involve Kaidou finding out about Saiki's powers by accident. At first, he's in shock but then realizes they can use these powers for good, like helping the school win a big competition against a rival school. They start training together in a comical way, with Kaidou trying to come up with strategies that work with Saiki's powers.
You can start by looking on fanfiction - specific websites. There are many platforms where fans share their works, and you can simply search for 'kaidou x aren fanfiction' in the search bar.
One idea could be to explore the origin of the Shun Shun Rikka. Maybe it has a deeper connection to an ancient ninja clan that was long forgotten. For example, Naruto discovers a hidden scroll that reveals the true power and purpose of the Shun Shun Rikka, and he has to go on a quest to unlock its full potential.
In Da Zhai Men, after Zhu Shun was wronged by the Bai family, he chose to hide his identity and escape from the martial world. However, Zhu Shun appeared again in the play and turned himself in to protect the Bai family and expose the truth. He went to the Supreme Court to surrender himself, and by stating the truth of the year, he implicated the people involved in the case, including Prince Zhan, Li Lianying, and Empress Dowager Cixi. Zhu Shun's surrender eventually led to Han Rongfa being put in prison, clearing the Bai family's name. Zhu Shun's actions displayed his friendship and sense of justice, which was admirable.
The audio novel, The Legend of Yao and Shun, was a novel that told the story of the Yao and Shun period in ancient Chinese legends. Yao and Shun were the two sages in ancient Chinese legends. It was said that they implemented a series of important political systems and moral standards, which had a profound impact on the development of Chinese feudal society. The audio novel Yao and Shun mainly narrated the political struggles, cultural exchanges, myths and legends of the Yao and Shun period.
Nendo could be a great addition. His simple - minded nature can add a lot of humor. For example, he could misunderstand the relationship between Saiki and Kaidou and try to get in on their 'adventures' in a really clumsy way.
Shun in this fanfic might show his loyalty, especially towards his friends and his Bakugan. He is also quite independent, preferring to do things his own way at times. Fabia is confident. She is not afraid to voice her opinions and her strategies, even if they might be different from others. She is also empathetic, able to understand the feelings of her Bakugan and her comrades.