Fanfiction.net is also a good place to search. There are many different categories and you can narrow down your search to find the 'rohan x josuke' fanfiction you're interested in. However, the quality can vary, so you might need to do some sifting through the results.
Fanfiction.net is also a popular place. There are many fanfic writers who contribute to the Josuke x Rohan category there. However, the quality may vary, so you might need to read a few to find the really good ones. Some might be more focused on their friendship, while others could explore a romantic relationship between them.
Some popular ones could be 'Sword of the Rohan' which is known for its epic battles and complex characters. Another might be 'Rohan's Quest', a story full of mystery and adventure.
There could be multiple factors. His role models, whether they were his teachers, older siblings, or people he read about in books, might have inspired him. Also, the realization that hard work brings rewards, like good grades, praise from others, and a sense of accomplishment, would have made him keep up his hardworking attitude.
I'm not sure specifically as I haven't read this novel. But generally, it might be about a character who is determined to stay in a marriage for various reasons like love, family values, or some hidden secrets that make divorce not an option.
Popular 'rohan x josuke fanfic' often focus on their unique dynamic. They might play up Rohan's eccentricity and Josuke's more straightforward nature. Also, a lot of them involve some sort of mystery or adventure that the two characters embark on together.