One common theme is friendship. Luffy and Chopper have a very special bond in the original series, and fanfics often explore and expand on that. They might write about how they support each other during tough times on their adventures.
In many 'robin x luffy fanfic', the theme of protection is present. Luffy is always ready to protect his crewmates, including Robin. And Robin, in her own way, also tries to protect the crew and Luffy. Their relationship in the fanfics also often reflects the theme of loyalty. They are loyal to each other and to the crew. This loyalty is what makes their relationship so endearing in the fanfics and is a key element that the writers like to explore.
One common theme is friendship. Sanji and Luffy have a strong bond in the original series, and in fanfics, this bond is often explored more deeply, sometimes in a way that blurs the line into a more affectionate relationship. Another theme could be adventure. They might go on new and unique adventures together that are not part of the original story.
One common theme is loyalty. Bartolomeo is extremely loyal to Luffy in the fanfics, just as he is in the original story. Another theme is friendship. Their bond is often explored and developed further.
One common theme is friendship. Luffy is known for making strong bonds, and with Shirahoshi, it's no different. Their friendship is often explored, like how they support each other.
Friendship is a very common theme. Since Robin and Chopper have different personalities, their friendship is often explored. For example, Robin's wisdom can guide Chopper, and Chopper's pure heart can bring out Robin's softer side.
One common theme is adventure. Since Luffy is an adventurer in One Piece and Lucy has her own adventures in Fairy Tail, it's natural for their fanfics to involve them going on exciting quests together.
One common theme is the strong emotional bond between Ace and Luffy. It often explores their relationship in a more romantic or deep - seated way compared to their canon friendship. Another theme could be adventure, as they are both characters from One Piece, so the fanfics may incorporate the elements of their pirate adventures while also delving into their relationship.
One common theme could be the exploration of their different personalities. Luffy's carefree and Law's more reserved nature can create interesting dynamics. Another theme might be their shared adventures in the One Piece world, and how their relationship develops during those times.
One common theme is protection. Luffy is always ready to protect Nami and in a family - fanfic context, this extends to protecting their 'family' within the crew. Another theme is growth. As they form a family - like bond, they both grow as individuals. Nami becomes more confident in her decisions and Luffy learns more about the importance of relationships other than just being comrades.
Often, the theme of adventure might be intertwined. Given that Luffy is all about exploring and Boa has her own story in the One Piece world. Their relationship could be set against the backdrop of new adventures they embark on together. Another theme could be the discovery of emotions. Luffy is not always in touch with his romantic feelings, and Boa has her own complex emotions, so fanfics may focus on how they come to terms with their feelings for each other.