It could be that the writer is trying to subvert the traditional view of Harry Potter. They might think that exploring a darker side of him, making him cold - hearted, could lead to an interesting and unexpected plot. For example, if Harry had been betrayed in a different way than in the original story, it could potentially turn him cold towards others. Another reason could be that the author simply has a different perspective on the character and wants to express it through fanfiction.
One possibility is if he faced extreme betrayal in fanfiction. For example, if his friends turned on him for some reason, it could lead him to become cold - hearted as a form of self - protection. Another factor could be if he lost someone very dear to him in a particularly cruel way and then closed off his emotions.
I don't think so. Harry Potter is known for his courage, loyalty and compassion in the official story. While fanfiction can explore different interpretations, making him cold - hearted goes against the essence of the character that most fans are familiar with. So it's not likely to be a common theme in fanfiction.
In certain 'Cold Hearted Harry Potter Fanfiction', the story might revolve around an alternate universe where Harry was raised in a different environment, like the Dursleys were even more cruel. This could lead to him developing a cold heart. He might enter Hogwarts with a distrust of everyone and not be as quick to make friends as in the original story. Instead, he could be more calculating and focused on his own survival and goals.
In fanfic, a tragic backstory that was different from his original one could lead to Naruto being cold - hearted. Maybe if he had been abandoned by the whole village instead of just being shunned by some, he could grow up bitter and cold. Also, if he had to make really tough decisions that cost him a lot, like sacrificing friends for the greater good in the fanfic world, it might harden his heart.
Well, first of all, a great knowledge of the Harry Potter universe is essential. You have to really know the characters, the plotlines, and the magic system inside out. Then, having a unique voice in writing is a big plus. If your writing style stands out, it'll attract more readers. Additionally, being able to build on the existing lore in interesting ways, like exploring the backstories of minor characters or creating new sub - plots within Hogwarts. And of course, being active in the fanfiction community, interacting with other writers and readers, can also contribute to being seen as a leader.
It could be due to a spell. There are many dark spells in the wizarding world that might cause a person to feel cold. For example, some curses can drain the warmth from a body. If Harry was targeted by such a spell, he would be cold. Also, it might be related to his emotional state. If he was feeling lonely or scared, it could make him feel cold inside, just like when people are in a bad mood in real life, they might feel colder than usual.
It could be related to some sort of external influence, like a curse or a dark chakra that has infected him. This could be slowly changing his personality from the warm - hearted Naruto we know to a cold - hearted version. For example, if there was a powerful enemy who placed a curse on him that targeted his emotions.
Some writers may be attempting to analyze the character from a different psychological perspective. By portraying Naruto as a cold - blooded killer, they could be exploring how his upbringing or the events in the Naruto universe could have potentially led to a different, more sinister outcome. It might also be a form of creative rebellion against the traditional view of Naruto as a hero. However, this is a very extreme deviation from the original character, and not all fans would be receptive to such a portrayal.
Maybe for the sake of novelty. People might be tired of the traditional good - vs - evil story in the Harry Potter world and want to explore a completely different take on the character. It could also be an attempt to show how power can corrupt, even someone like Harry who was initially on the side of good.
I can't really think of any valid reason. It might be a completely misinformed idea. Maybe someone who is not very familiar with either Harry Potter or Vergil's works just made a wild and incorrect assumption. But in reality, there is no connection between them in terms of story, theme, or origin.