He might lose his connection with his human friends. As a full demon, his instincts could become more savage and he might not be able to control his power as well as he did when he was half - demon. His appearance would also change completely, perhaps becoming more fearsome and less recognizable to those who knew him before.
Well, if Inuyasha turns into a full demon in fanfiction, his power level would skyrocket. He'd likely have enhanced physical abilities like strength, speed, and endurance. However, his personality would probably change a great deal. He might become more arrogant and less approachable. His sense of morality could also be warped as the demon nature takes over completely. And his place in the demon world would change. He might be seen as a threat by some demons and a potential ally by others, depending on how they view his new - found power.
In fanfiction, if Inuyasha becomes a full demon, his relationship with Kagome could be severely tested. Since he's a full demon now, his values and priorities might shift. He could be more focused on power and domination, which would be in contrast to Kagome's kind and empathetic nature. Also, he would no longer have the internal struggle between his human and demon sides, but this new single - mindedness could lead to new conflicts in the story.
Inuyasha's character would lose some of his charm. As a full demon, he would no longer have the endearing qualities that came from his human half. His sense of humor might disappear. He would be more focused on survival of the fittest in the demon world. His loyalty to his friends would be tested as his new demon nature might not value the same things. His character would become more one - dimensional in a sense, as the complexity of his half - demon state is removed. Instead of having the internal struggle that made him interesting, he would just be a full - fledged demon with all the typical demon traits like aggression and a thirst for power.
If Tanjiro becomes a demon in fanfiction, he might lose his sense of humanity. His relationships with his friends and family would be severely strained. For example, his sister Nezuko, who is also a demon, might be affected in unexpected ways. He could struggle with his newfound bloodlust and the need to consume humans, which goes against his original kind - hearted nature.
If Harry Potter becomes a demon in fanfiction, his relationships would be severely affected. His friends like Ron and Hermione would be very confused and possibly afraid of him. They might try to find a way to reverse the transformation. And Hogwarts itself would be in chaos. The teachers would be divided on how to deal with him, some might want to help him while others might see him as a threat to the safety of the school.
If Naruto becomes the Demon of the Mist in fanfiction, he might start to lose his sense of self. The title 'Demon of the Mist' implies a certain level of malevolence and mystery that is quite different from Naruto's usual sunny disposition. His ninja way would be severely tested as he tries to balance the new, darker identity with his old values. Maybe he'd be forced to fight against his former allies who see him as a threat now. Also, his appearance could change to something more in line with the image of a demon, which would be a shock to those who know him well.
If Naruto becomes a demon in a fanfic, it could lead to a whole new set of adventures. He might be shunned by the village he once protected. However, this could also be an opportunity for him to discover a new side of his power. He could use his demonic powers for good, but first he would need to overcome the prejudice against him. His relationships with characters like Sasuke and Sakura would be put to the test as they might not trust him immediately.
One possible fanfiction could be about Inuyasha in his full demon form and Kagome's journey to understand and reach out to him. Maybe she uses her spiritual powers to calm him down when he's on the verge of losing control. It could explore their relationship dynamic in this unique state of Inuyasha.
Inuyasha might develop more self - control. If he has new powers from becoming this 'demon', he would need to control his impulses to use them recklessly. His character could become more introspective as he tries to understand what has happened to him and how to reverse it if possible.
In fanfiction, if Danny Phantom becomes a full ghost, he might gain enhanced powers. He could have better control over intangibility and invisibility. Maybe he could travel through different dimensions more easily, like the Ghost Zone. Also, his appearance might change more towards a typical ghostly form, with more ethereal features.
There would likely be a lot of initial resistance from other characters. After all, Kagura is associated with Naraku and Sesshomaru has his own goals and pride. But as the story unfolds, they might start to see the good in each other. Kagura could help Sesshomaru become more in touch with his emotions, and Sesshomaru could offer Kagura protection and a new sense of purpose.
Well, if Link were to become part of a Twilight fanfiction, it would be a whole new adventure. His character would be molded by the unique atmosphere of the Twilight world. He could gain new powers, like the ability to manipulate twilight energy. This would change his combat style completely. Also, the story could explore different aspects of his personality. In the Twilight fanfiction, he might be more brooding or have a deeper connection to the spiritual side of things. And his interactions with other characters, both new and old, would be different. For example, his relationship with Zelda could take on a new dimension as he is now in this Twilight - influenced world.