Her relationships would become more complex. Her family might not recognize her at first, and when they do, they might be afraid. Her friends could be both in awe and a bit scared of her new identity.
If Arya Stark becomes the Stranger in a fanfic, her relationships would be drastically altered. With her family, like Sansa, there would be a sense of estrangement. Sansa, who has always seen Arya as her sister, might not know how to deal with this new, more otherworldly Arya. Her relationship with Jon could also change. Jon, who has always been protective of Arya, might find it hard to understand her new motives and actions as the Stranger. And as for her friends, like Gendry, he might be a bit intimidated by her now. Arya was already a force to be reckoned with, but as the Stranger, she would be on a whole new level. This new identity would put a strain on her relationships as people try to figure out where they stand with her.
If Arya becomes the Night Queen, her personality might become more cold and calculating. She has always been a survivor, but as the Night Queen, she would need to be more ruthless to control the White Walkers. Her sense of humor and playfulness might disappear as she takes on this dark and serious role.
She might use her new role to bring justice in a different way. Maybe she'd secretly punish the corrupt nobles who escaped regular justice. The Stranger is often associated with death and the end, so Arya could be the one to end the reigns of tyrants in the fanfic world.
Romantically, if Hermione becomes a boy, she might attract different people. Maybe some of the female students who were just friends with her before start to have a crush on her. And she would have to figure out how to handle these new romantic interests while still being true to herself and her old friendships.
Arya's identity as a Stark would be more deeply ingrained in her. She would start to embrace all the values that the Starks stand for. She might even try to teach these values to the people of the North. Her development would also involve her coming to terms with her past as a Faceless Man. She would decide how much of that part of her should be part of the new Stark legacy she is building.
With his friends in Konoha, like Sakura and Kakashi, there would be a major shift. Sakura might initially be conflicted between her loyalty to the village and her friendship with Naruto. Kakashi, being a more experienced shinobi, might understand Naruto's reasons better but still be bound by his duties to the village. Overall, Naruto's departure as a nukenin would create a lot of emotional turmoil among his relationships.
If Naruto becomes cold, his relationship with Hinata would be severely affected. Hinata, who loves him for his warm heart, might be at a loss. Naruto might start to push her away, not allowing her to get close. His friends from Team 7 might try to bring back the old Naruto, but his coldness would create a rift between them.
If Arya and Ramsay interacted, it would likely be a battle of wits. Arya is smart and resourceful, while Ramsay is cruel and cunning. Their interactions could lead to a lot of unexpected twists. For instance, Arya might be able to expose Ramsay's true nature to more people, which could change the political landscape in Westeros.
If Bella becomes a banshee, her relationship with Edward would be very different. He would be more protective of her as she has a new and potentially dangerous power. He might also be a bit wary as banshees are known for their wailing which could attract unwanted attention. With Jacob, he might see her as even more of an enigma and be more drawn to her in a way, since she's now a more powerful supernatural being.
If Arya Stark becomes the Night Queen in a fanfic, it would be quite a shock to the system. Arya has always been a fighter against the forces of darkness, so her becoming the Night Queen would be a complete role reversal. One possible plot could be that she is forced into this position against her will, perhaps by some ancient magic or a deal gone wrong. Then, she has to navigate her new identity while still holding on to some of her old values, which could lead to a lot of internal conflict.
His relationship with Sasuke would be greatly affected. Sasuke might see Naruto as a completely different person now that he has become the Nine - Tails. There could be a sense of fear or at least a new level of caution from Sasuke. They might have to re - establish their bond, as Naruto's new form could be a threat in Sasuke's eyes.