As of now, in the manga, the identity of Luffy's mom remains unknown. There have been many theories and speculations among fans, but no official confirmation.
Rebecca could potentially be in Luffy's harem. After Luffy helped her in Dressrosa, she might develop feelings for him. She is a strong - willed and kind - hearted character. Another could be Shirahoshi. Luffy has a special connection with her as he saved her from being captured. Her gentle and innocent nature would contrast with some of the other more assertive members of the harem.
There could be an original character created just for the fanfiction. A woman with a kind heart but a tough exterior, who was a great fighter. She could have met Luffy's father during a battle and they fell in love, and she became Luffy's mother.
Daniel Defoe is often regarded as the 'grandfather of English novel'. His works, like 'Robinson Crusoe', were among the first to have the characteristics that we now associate with the modern novel, such as a focus on an individual's experiences and a detailed, realistic portrayal of life.
H.G. Wells is often considered the 'grandfather of science fiction'. His works like 'The War of the Worlds' and 'The Time Machine' were highly innovative and set the stage for many of the science fiction tropes we know today.
The theme of acceptance is quite common. Fem Luffy often has to be accepted by the other characters in the story. This could be because she's different due to her gender or her slightly different personality traits. Also, the theme of self - discovery is prevalent. As fem Luffy navigates the pirate world, she discovers more about herself, her abilities, and her place in the grand scheme of things.
Well, here's a story. There was a beautiful princess. She was locked in a high tower by an evil witch. Her grandfather had left her a magic key before. She used the key to open the door of the tower. Then she started her journey to find the witch and break the spell. Along the way, she met a brave knight and they fought together against the witch.
The World Government could be the main antagonist in a more complex way. They could be secretly manipulating events to pit Dragon and Luffy against each other. For example, they could spread false rumors about Luffy being a tool of the revolutionaries, which would make other pirate crews and kingdoms target him, and at the same time make Dragon look bad for having a son who is causing so much chaos. This would force Dragon and Luffy to either fight each other or find a way to clear their names together.
In 'Shanks Saves Luffy' fanfiction, Shanks and Luffy are the central figures. However, characters from Shanks' crew could also be involved. They might be there to assist Shanks in the rescue mission or have some sort of back - story related to why Shanks is so determined to save Luffy. Additionally, any new characters created specifically for the fanfiction, perhaps a powerful being who is the root cause of Luffy's danger, could also be main characters in the story.