Tanjiro and Giyuu have a sort of mentor-student relationship. Giyuu offers guidance and support to Tanjiro on his journey, and Tanjiro learns valuable lessons from him. They also develop a sense of camaraderie as they face the challenges of the demon world together.
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.
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.
One common theme is the exploration of their contrasting personalities. Shinobu is often seen as more outgoing and mischievous while Giyuu is more stoic. Fanfics like to play with how these two different personalities interact and find common ground. Another theme is the idea of healing. Given their experiences in the main story, fanfics may show how they heal each other's emotional wounds.
The themes usually include unspoken love. Since both characters are not very vocal about their feelings in the original story, fanfictions often explore the idea of them having deep, unspoken emotions for each other. Also, there's the theme of support. They support each other in battles against demons, and this aspect is often elaborated on in fanfictions, like how Shinobu's medical knowledge helps Giyuu when he's injured.
One great 'shinobu and giyuu fanfic' is 'The Unspoken Bond' which delves deep into their complex relationship. It shows how they gradually come to understand and support each other in the face of various challenges in the Demon Slayer world.