In this fanfiction, Naruto and Greyfia's interaction could be very interesting. Naruto, with his boisterous personality, might try to involve Greyfia in his crazy adventures in the Highschool DxD. Greyfia, on the other hand, would be the more cautious one. She might initially try to keep Naruto in line, but as she gets to know him better, she would start to appreciate his unique perspective. For example, when they are faced with a difficult situation, Naruto's quick thinking and improvisation could amaze Greyfia, and she might start to rely on his skills more. At the same time, Naruto could learn from Greyfia's grace and diplomatic skills, which are very different from what he is used to in the ninja world.
Well, in a 'Naruto x Greyfia Highschool DxD' fanfiction, perhaps Naruto is a new transfer student in the Highschool DxD. Greyfia could be a popular student there. Naruto's positive and energetic attitude might attract Greyfia's attention. They could start off as friends and gradually develop a deeper relationship. Maybe they get involved in the supernatural battles of the DxD world together, with Naruto using his Rasengan and other jutsu while Greyfia uses her demonic powers. And as they spend more time together, they learn from each other's worlds and values.
One interesting concept could be the power dynamics. Since Black Goku is a powerful and often malevolent version of Goku, exploring how their powers interact in a fanfiction can be exciting. For example, they might have an epic battle where their similar yet different fighting styles clash.
Character development is also crucial. In many such fanfictions, Female Goku Black may start as a villainous or at least antagonistic character. But as the story unfolds, she might change due to her interactions with Goku. This transformation can be really interesting to follow. For example, she could start to question her own motives or even develop feelings for Goku, which is a big shift from her initial stance.
As the story progresses, some fanfictions might explore a begrudging respect. Despite their differences, they recognize each other's power and fighting abilities. For example, they could have a series of battles where they start to understand each other's strategies better.
One idea could be that Goku and Goku Black are forced to team up against an even greater threat from another universe. They start to understand each other's fighting styles during the battle and gradually develop a grudging respect for one another.
Well, Goku Black could be the more dominant character. His dark nature gives him a different kind of power. He doesn't have the same moral constraints as Goku. This could allow him to make more ruthless and effective decisions in battle. He might be able to outmaneuver Goku if he plays his cards right.
Issei would be very likely. Since Issei is the main character in DxD, his curiosity and his own pursuit of power would make him interested in Goku. They could train together and learn from each other's abilities. Also, Rias would interact with Goku. As a powerful devil, she would be intrigued by Goku's power and his different way of approaching battles.
One popular 'goku x female goku black fanfiction' might be 'The Unlikely Bond'. It explores a unique relationship between Goku and Female Goku Black. In this fic, they start off as enemies but gradually discover they have more in common than they thought.
Well, a Goku x Caulifla x Kale fanfiction could potentially be about their adventures together in a new setting. Maybe it could involve them teaming up against a powerful enemy and during that time, their relationships grow and develop in interesting ways. However, 'lemon' usually implies some inappropriate or adult - themed content, which is not something I would encourage. So if we focus on a non - inappropriate version, it could be a story full of friendship and mutual growth.