Tumblr can be a source as well. There are often fanfic recs (recommendations) on Tumblr blogs dedicated to Bleach (the series Renji and Rukia are from). You might also find some original fanfics posted directly on Tumblr, though they might be shorter and more in the form of drabbles compared to the longer fics on AO3 or Fanfiction.net.
Fanfiction.net is also a good place. There are numerous Renji x Rukia fanfics there. However, the quality may vary, so you might need to read the reviews or summaries before choosing a fic. Some of the fics on this site are really old and have a charm of their own as they were written closer to the release of the original series.
You can try Archive of Our Own (AO3). It has a large collection of fanfics, including many about Renji and Rukia. The site is well - organized, and you can easily search for the specific pairing.
You can try some popular fanfiction websites like Fanfiction.net or Archive of Our Own. These platforms usually have a large collection of fanfictions, and you can search for rukia x renji fanfiction specifically. Just use the search bar and type in the relevant tags.
One popular trope is the 'reunion' trope. Since they have a long history together in the Bleach universe, many fanfics focus on their reunions after long separations, like when Renji returns from a difficult mission or when Rukia is freed from certain situations. It's always an emotional and impactful moment in these stories.
Another option is to follow some Bleach fanfic communities on social media platforms. There could be groups on Facebook or Tumblr where fans share their 'ichigo x rukia fanfic'. However, you need to be a bit more careful on these platforms as the quality and content can vary a lot.
I'm not sure about specific titles off - hand, but you can try looking on fanfiction.net. There are usually a lot of 'bleach renji x rukia fanfic' there. You can search by the tags 'Renji', 'Rukia' and 'Bleach'. Usually, the ones with high ratings are quite good. Some might explore their relationship in different AU (Alternate Universes) like a modern - day setting or a fantasy world different from the original Bleach universe.
One popular Renji x Rukia fanfic is 'A Bond Unbroken'. It beautifully portrays their relationship's growth from their early days in the Soul Society. The story focuses on how they overcome various challenges together.
If we think about rukia, she is a character with a complex past and a strong sense of duty. Renji, her long - time friend and ally, has his own journey of growth. In rukia renji fanfictions, they might be shown as having a connection that goes beyond the ordinary, with rukia's cool exterior melting in front of renji, and renji being able to be more vulnerable around rukia. This can be explored in various non - adult ways in fanfiction.
The theme of friendship - turned - love is often explored. They start as friends or comrades in the Soul Society, and then their relationship blossoms into something more. There's also the theme of overcoming obstacles. These obstacles can be external, like the rules of the Soul Society, or internal, like their own insecurities. For instance, Renji may struggle with feeling worthy of Rukia's love, and the fic will be about how he overcomes that self - doubt while they build their relationship.
Another way is to join Bleach - related fan groups on social media platforms. People in these groups often share and recommend good fanfictions. You can ask specifically for rukia and renji married fanfiction, and they'll likely be able to point you in the right direction.
The theme of sacrifice is quite common too. Renji may be willing to sacrifice his own well - being or position for Rukia's sake. Also, the theme of self - discovery. Through their relationship, they both discover new aspects of themselves. For instance, Rukia might discover a stronger side of herself because of Renji's support, and Renji might discover his capacity for deep love.
A popular 'ichigo x rukia x renji fanfiction' is 'Soul Connections'. It starts with a strange phenomenon in the Soul Society that links the destinies of Ichigo, Rukia, and Renji. As the story progresses, we see how their pasts, especially Rukia and Renji's history together in the Gotei 13, influence their present relationships with Ichigo. The fanfiction does an excellent job of portraying the growth of their relationships, from initial misunderstandings to a deep and unbreakable bond.