In a Giyuu x Shinobu fanfic, the setting and plot can vary widely. Some might be set during the main events of the Demon Slayer universe, with them facing demons together. Others could be more of an alternate universe story, where they meet under different circumstances, like in a modern - day high school AU. The fanfic could also delve into their backstories and how those experiences shape their relationship. For instance, Shinobu's past with her sister could play a role in how she opens up to Giyuu, and vice versa for Giyuu's own traumas.
I would recommend 'Whispers of the Heart' for Giyuu x Shinobu fans. This fanfic focuses on their unspoken understanding. It's full of small moments that build up their relationship, like when Shinobu leaves a small flower on Giyuu's doorstep as a sign of her care. Also, 'Shadows and Sunlight' is worth checking out. It has a great plot that involves them having to go on a secret mission together and how that journey changes their relationship from colleagues to something more intimate.
One common theme is the exploration of their relationship. Given their different personalities in the original work, fanfictions often focus on how they bridge the gap between them, like how Giyuu's stoicism and Shinobu's more cheerful yet calculating nature interact.
The following were some of the recommended ancient novels that had transmigrated into babies: " Family with Hairpins,"" Reborn Prince Princess Concubine,"" I'll Never Change My Love in This Life,"" Evil King Lasts on His Body: Picking Up a Cute Item to Raise His Concubine,"" I Really Don't Want to Become a God After Ten Thousand Years,"" Demon Emperor's Extinction: The Foppish and Arrogant Concubine," and so on. These novels all told the story of the protagonist transmigrating into a baby. The female protagonist was doted on by the whole family in ancient times and enjoyed a superior life. These novels were suitable for readers who liked ancient novels.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you can easily search for 'female giyuu fanfiction' using the search bar. Another option is FanFiction.net, which also has a good number of such stories.
One common theme is the exploration of their contrasting personalities. Shinobu is often seen as more light - hearted and talkative, while Giyuu is quiet and reserved. Fanfictions usually play with how these differences can either create friction or bring them closer together.