Well, another option could be to check out relevant fan communities on social media platforms. For example, on Reddit, there might be subreddits dedicated to this particular fandom where fans share their fanfictions or know where to find them. You could also search on Tumblr, as it has a large community of fanfic writers and readers.
You can try looking on some popular fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. They usually have a wide range of fanfictions, and you might be able to find ones related to Sword User ID and Rias' love there.
I'm not sure specifically for Sword User ID and Rias love fanfiction, but in general, in the world of fanfiction, some authors become well - known within their fandoms. You can often tell by the number of views, reviews, and bookmarks their stories get on platforms like AO3 or FanFiction.net.
One great example could be a fanfic where the Sword User OC saves Rias from a dangerous situation, and from that moment, a deep bond forms between them. The OC's unique sword skills add an exciting element to their relationship as they face various challenges together in the underworld.
A unique way to develop their relationship could be through a magical bond. Maybe the sword of the OC has a special magic that links it to Rias. As they explore this magic together, they grow closer. For example, the sword might have the power to show their shared memories or future possibilities, which would make their relationship more complex and deep.
There are probably some 'Harry Potter and Rias Love' fanfictions. Usually, in these types of crossovers, the authors might start by establishing how the two characters from different universes meet. Maybe Harry gets transported to Rias's world or vice versa. Then, they would build on their relationship, perhaps starting as friends and gradually developing into something more. It's all about the creativity of the fanfiction writers, and different writers will have different takes on this unique pairing.
A major challenge would be the time - space aspect. Naruto's world has its own timeline and geography, and Rias' world is also different in this regard. If they are to have a love story, how do they manage to be in the same place at the right time? And when they are apart, how do they maintain their relationship? These are all difficult questions that fanfiction writers need to address.
One possible fanfiction idea could be that Rias' sick brother is a key factor in a power struggle within their supernatural world. Naruto, being an outsider with his own set of skills and values, could get involved. Maybe he forms an alliance with Rias to protect her brother from those who would use his illness to their advantage.
One reason is the chemistry between the two characters. Rias is a strong and alluring character, and Issei is a relatable protagonist. Their relationship has a lot of potential for different storylines, like how they grow closer and face challenges together.
One popular one might be 'Issei and Rias: The Eternal Bond'. It beautifully depicts their relationship growth with lots of romantic moments and challenges they face together.
Some niche anime - related forums might also be a good source. Members often share their own written fanfictions or recommend ones they've read. However, the search might be a bit more difficult compared to the larger fanfiction platforms, but it can be worth it as you might find some unique stories.