Well, for a unique relationship development, Emrys could act as a mentor to Belle in understanding magic, which in turn makes Rumplestiltskin (Gold) jealous. This jealousy could lead to Rumplestiltskin trying to prove himself to Belle in new ways. He might start to let go of some of his darker tendencies as he sees Belle growing closer to Emrys in a platonic way.
A unique way could be that Belle discovers she has a hidden power that is connected to Emrys' magic lineage. This makes Rumplestiltskin both proud and afraid for her. He is proud because she is becoming more powerful but afraid that she will be drawn away from him. Emrys then becomes a sort of protector for Belle as she tries to master this new power, and their relationship evolves in a complex triangle.
One way is to have Rumplestiltskin and Emrys start off as enemies. But then, through Belle's influence, they find common ground. Maybe Belle is in danger, and they both realize that they need to work together to save her. As they do so, they begin to respect each other. And Belle, seeing this new dynamic, starts to see Rumplestiltskin in a new light, and their relationship deepens in a different way than before.
One possible fanfiction could be about how Rumplestiltskin, with his dark magic, crosses paths with Belle, his love interest. Emrys, who is Merlin in some lore, might be a guide or a powerful figure who tries to balance things. And Harry, coming from the wizarding world, could be brought into their realm by some magical accident. He might initially be confused but then use his skills to help or cause chaos, depending on the plot.
Imagine a scenario where a magical artifact is at the center of the story. Rumplestiltskin wants it for his collection and power - hoarding. Harry stumbles upon it first, not fully understanding its significance. Belle, who has knowledge of such artifacts through her time with Rumplestiltskin, warns Harry. Emrys, sensing the chaos that could ensue if Rumplestiltskin gets his hands on it, decides to get involved. He teams up with Harry and Belle to outwit Rumplestiltskin, leading to a series of magical battles and moral dilemmas that test each character's true nature.
A plot could revolve around a time - travel element. Belle somehow gets sent back in time and meets a younger version of Rumplestiltskin before he became so consumed by power. Emrys could be the one who has the power to send her back and also to bring her home. Gold in the present realizes what has happened and tries to find a way to bring Belle back while also fearing how she might change the past.
Rumplestiltskin is one of the main characters. He is often the center of the story due to his complex personality and his many powers. Belle is another main character. Her love for Rumplestiltskin and her own strong will make her an important part of the story. Emrys, as the third main character, can add an element of mystery. Emrys might be a powerful wizard from a far - off land whose magic intersects with the lives of Rumplestiltskin and Belle. In some fanfictions, Emrys could be the one who helps Belle understand Rumplestiltskin better or vice versa.
One great fanfiction could be 'The Unlikely Bond'. In this story, Rumplestiltskin and Belle's relationship takes a new turn as Emrys plays a mysterious role in bringing them closer. It has a lot of emotional depth and beautiful descriptions of their interactions.
For Gaston, you could develop his character by showing his vulnerability. Maybe he has a fear of being alone forever, which is why he's so desperate to marry Belle. With Dark Belle, you could explore her darker side more. For example, she could have a temper that she usually keeps in check. You can also have them influence each other. Gaston could make Dark Belle more assertive in a different way, and Dark Belle could make Gaston more introspective.
For Naruto and Hinata, their relationship could develop in a unique way if Hinata starts teaching Naruto some of the more refined aspects of the Hyuga clan's techniques. This would create a new level of closeness as Naruto respects Hinata's skills. And with Tenten, she could be the one who arranges little 'get - togethers' for the three of them, which slowly builds a stronger bond between all of them.
Their relationships could be developed uniquely by having them participate in a magical tournament that's not like the Triwizard Tournament. They are on different teams but have to cooperate secretly to overcome some corrupt judges. Draco might start to see Harry and Hermione in a new light as they work together to expose the wrongdoings. This shared experience outside of the normal Hogwarts rivalries can bring them closer.
Their relationships can be developed uniquely by having them participate in a mission that requires them to rely on each other's skills in unexpected ways. For example, Ino's mental abilities, Naruto's brute strength and positive energy, and Sasuke's strategic skills could combine to solve a mystery that has been plaguing the village. This would force them to respect and trust each other more.
In terms of the Cullens' family relationships, in a split second, Carlisle could be put in a situation where he has to choose between his family and his principles. For example, if a new vampire law is created that goes against his beliefs, and his family is in danger because of it. This would force the family to re - evaluate their relationships with him and with each other as they deal with this new situation.