Another place to find them is FanFiction.net. There are many RWBY fans who post their works there. However, the quality can vary, so you might need to read the summaries and reviews before choosing a story. Some stories might be more focused on their relationship development, while others could be action - packed adventures involving the two characters.
Reddit can also be a good source. There are RWBY - related subreddits where fans might share links to their favorite Emerald x Mercury fanfictions or discuss the best ones they've read. You can join these communities and ask for recommendations. This way, you can get some insider tips on the really good fanfictions in this category.
There's 'Mercury and Emerald: A Different Path'. This fanfic takes a unique approach by exploring what would happen if they decided to break away from their original group. It's an interesting read as it shows their growth as individuals and as a duo.
You can start by looking on popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of RWBY fanfictions, and you can easily search for those specifically related to Mercury.
A really cool fanfiction is 'Mercury and Emerald in the Realm of Shadows'. It takes them into a dark and mysterious realm where they have to fight to survive and rely on each other more than ever. 'Emerald's Secret and Mercury's Promise' is another good one. Here, Emerald has a secret that she's afraid to share, but Mercury's loyalty to her is unwavering. And 'Mercury and Emerald: Facing the Past' where they are forced to confront their past misdeeds and try to make amends while still being the characters we know from RWBY.
The RWBY universe itself is full of mystery and action. Fanfiction about Mercury and Emerald can add more depth to their characters and their place in this universe. It can also create new storylines that might not be explored in the main series, which is very appealing to fans.
There might be a fanfiction where Emerald and Mercury are forced to team up with some unlikely allies. This would create a lot of interesting dynamics as they have to adapt to new ways of working and new personalities. Maybe they start to see things from different perspectives and it changes their relationship for the better.
First, study their characters well. Watch the RWBY episodes that feature Mercury and Emerald to understand their personalities, motives, and relationships. Then, come up with an interesting plot. It could be about a mission they go on, a conflict between them, or how they deal with a new threat in the RWBY world. Don't forget to give them unique voices in your writing, making sure their dialogue reflects who they are.
There's a fanfiction where mercury and emerald are on a mission together. In this story, their teamwork gradually turns into a deeper connection. It shows how they come to rely on each other and develop feelings over time. It's quite engaging as it combines action and their growing relationship.
Redemption is also a theme. Mercury, having been part of some not - so - good deeds in his past, might find redemption through his relationship with emerald. It's about changing for the better because of someone you care about. This is shown in many fanfictions where he tries to make up for his past actions.
Archive of Our Own (AO3) is a great place to start. It has a large collection of fanfictions from various fandoms, including RWBY, so there's a high chance of finding Cinder x Emerald ones there.
One popular 'Mercury x Emerald' fanfic is 'Mercury's Emerald Bond'. It delves into their relationship in a really interesting way, exploring how they might interact and support each other in different scenarios. Another great one could be 'Emerald and Mercury: Unlikely Allies' which shows their journey from being strangers to having a strong connection.