One great Portgas D Ace x Reader fanfiction is 'A Bond Beyond Flames'. It beautifully captures Ace's adventurous spirit and how he forms a deep connection with the reader. The story is filled with action-packed scenes on the high seas and tender moments between the two characters.
The relationship development between Ace and the reader needs to be believable. It can't be too rushed. Maybe they start as comrades, sharing adventures and gradually realizing their feelings for each other. Also, the fanfic should fit well within the One Piece universe in terms of the setting and other characters.
One common theme is adventure. Since Ace is a pirate in One Piece, many fanfictions incorporate the reader into his exciting adventures on the high seas. They might go on treasure hunts or battle against other pirates together.
You can try fanfiction websites like Archive of Our Own (AO3). There are a large number of Portgas D Ace x Reader fanfictions on it. You can search by tags to find the ones that suit your taste, such as 'romance' or 'adventure' tags.
One common theme is his relationship with his brothers, Luffy and Sabo. There are many fanfictions that explore their childhood memories and how their bond has influenced Ace's life. Another theme is Ace's time in the Whitebeard Pirates. Fanfictions often focus on his interactions with his crewmates and how he grew as a person there.
Emotional depth is another important aspect. Since Ace has such a complex backstory and relationships, a good fanfiction will explore his emotions. It could be his feelings towards his brothers, his crewmates, or his own identity as a pirate and the son of Gol D. Roger. Also, world - building, if the story takes place in a new location or expands on the One Piece world, should be believable and add to the overall story.
There's also 'Naruto and Ace: Cross - World Bonds'. This fanfiction focuses on the friendship that develops between Naruto and Ace when they meet in a strange in - between world. It delves deep into their personalities and how they learn from each other. For example, Naruto teaches Ace about the importance of having a strong will in a different way than what Ace is used to in the One Piece world.
You can start by looking on fanfiction platforms like Archive of Our Own (AO3). It has a large collection of fanfictions about various characters, including Portgas D Ace. Another good place is Fanfiction.net. Just use the search bar and type in 'Portgas D Ace' to find relevant stories.
The most common theme is probably the transformation itself. Writers often focus on how Ace becoming female changes her perspective and the way she approaches life. Power and strength are also themes. Does being female affect her power? Some fanfictions show her having to prove herself more because of her gender. Also, loyalty. Her loyalty to her friends and crew remains a central theme, but it's often explored in new ways due to her new identity as a female in these fanfictions.
A good Naruto and Portgas D. Ace fanfiction often has a well - thought - out plot that combines the elements of both universes in a believable way. For instance, how the chakra system in Naruto might interact with the devil fruits in One Piece.