Perhaps a foreign exchange student who is also a baseball enthusiast. She joins the school and starts interacting with the Diamond no Ace team. Her different perspective on baseball and her charm could make her a potential 2nd lover for one of the players. Also, a girl from a rival school who initially has a competitive attitude but then falls for one of the players could be another character to consider as a 2nd lover in the fanfic.
A potential 2nd lover character could be a childhood friend of one of the players who has just moved back to town. She has always had feelings for him, but he was so focused on baseball before that he didn't notice. Now that she's back, she could be the 2nd lover in the fanfic. Another option could be a coach's daughter. She's around the team a lot and starts to develop feelings for one of the boys on the team.
One plot idea could be a new character joining the baseball team and becoming a 2nd lover to one of the main characters, causing some drama among the team. Another could be a time - travel plot where a character goes back to change an event in the Diamond no Ace story and in the process finds a new love.
A young and brash rookie pilot could be a great main character. He's full of enthusiasm but lacks experience. He has to learn quickly in the harsh reality of war. Maybe he idolizes an older, more experienced pilot who becomes his mentor.
It could be a young couple who were separated due to family issues. For example, the boy's family didn't approve of the girl and they were forced apart. Then the main characters would be the boy and the girl.
Obviously Naruto himself. There might also be Sasuke, as he is Naruto's rival and friend. Sakura could be there too, maybe she is curious about Naruto's new identity. And Kakashi could play a role in guiding Naruto about his connection to the pink diamond.
The main characters could be a brave bellow warrior named Bane who is on a quest related to the lemon. And perhaps a diamond princess named Della who gets involved in Bane's journey either as an ally or an obstacle.
The offspring of Todoroki and Momo could be great main characters. With Todoroki's ice - fire quirk and Momo's creation quirk, their child might have a really unique and powerful combination of abilities. The character could struggle with the high expectations that come from having such powerful parents.
Obviously, Ranma and Akane are prime candidates. Their relationship is central to the series, so a pregnancy between them would create a lot of drama and interesting storylines. Shampoo could also be involved in some way. Maybe she's jealous and tries to interfere, or she could be surprisingly helpful. Genma, Ranma's father, would also play a role. He might have some old - fashioned or comical ideas about the situation.
Obviously Skye herself is the main character. There could be a love interest who is the father of the baby. Her best friend could also be an important character, providing emotional support and practical help like going to doctor's appointments with her.
Well, a really cool Diamond no Ace fanfic is 'Team Spirit'. This one really emphasizes the importance of team spirit in baseball. It shows how the characters support each other and work together to win games. Another one is 'The Rookie's Rise'. It follows a rookie player as he tries to make his mark in the team. It's full of challenges and how he overcomes them. And 'Baseball Bonds' is a fanfic that focuses on the strong bonds formed between the players through the game of baseball.
One common theme is self - discovery. The OCs often start out not fully knowing their potential in the baseball world of Diamond no Ace, and as the story progresses, they discover their strengths and weaknesses. For example, an OC might realize she has a great batting eye but needs to work on her speed.