The key elements in Sanji's back story are his family, the Vinsmokes. His different nature compared to his siblings is also important. And of course, his love for cooking.
I think it might have been a character introduced to add depth to Sanji's backstory and motivations. But without more context, it's hard to say for sure.
For Nami, her intelligence and cunning are key. She could use her smarts to get Sanji out of trouble in the fanfiction. Also, her love for money and treasure can add an interesting dynamic. For example, she might convince Sanji to go on a dangerous adventure in search of a valuable item, promising him new ingredients for his kitchen.
Well, without more context, it's difficult to say precisely. It could be that Sanji is a victim in this ghost story, constantly haunted by a malevolent spirit. Maybe the story is set in a small, isolated town where Sanji discovers some dark secrets related to the ghosts that are terrorizing the place.
Another characteristic is the exploration of new relationships. Since Sanji is a popular character, in female - centered fanfiction, new relationships with female characters can be created. These relationships can range from romantic to platonic, and they add new dimensions to Sanji's character. For instance, he might form a strong friendship with a female swordsman in a fanfic.
Sanji's back story is quite interesting. He grew up in the Vinsmoke family, which was a rather cruel and power - hungry family. Sanji was different from his siblings, he had a kind heart. His father was disappointed in him for his soft - heartedness and lack of the 'killer instinct'. Sanji was constantly bullied by his brothers. But he found solace in cooking. This led to his great passion for cooking later in life.
In zoro x sanji fanfics, one of the main things is the focus on their character development in relation to each other. They are both strong - willed characters, and fanfics show how they can grow and change because of their interactions. Also, many of these fanfics tend to set up unique scenarios for them. For example, they might be stranded together on an island, forcing them to rely on each other more than usual. This helps to bring out different aspects of their relationship that we don't always see in the main story. And the humor aspect is also quite prevalent. Their banter and arguments can be a source of great comedic moments in these fanfics.