I don't think so. Naruto is known for his strong sense of justice, his loyalty to his friends, and his will to protect his village. These qualities are completely opposite to what a cold - hearted killer represents. Fanfictions that deviate too much from the original character traits may not be as popular among the mainstream Naruto fanbase.
One potential enemy could be Danzo. In the original series, Danzo had many shady dealings. If Naruto turns cold - hearted, he might see Danzo as a threat to Konoha's true peace and go after him. Another enemy could be Kabuto. After his experiments and all the chaos he caused, a cold - hearted Naruto might not tolerate his existence. Also, there are the Akatsuki members. Naruto could target them in a more ruthless way, especially Pain, who once attacked Konoha and caused a great deal of destruction.
Some writers could be exploring the 'what if' scenarios. They might wonder what would happen if Naruto had a different upbringing or faced different traumas that could turn him into a cold - hearted killer. It's a way of delving deeper into the character's potential under extreme circumstances. Also, it could be a form of creative rebellion against the typical positive portrayal of Naruto in the main series.
One popular theme is the transformation of Naruto into a cold - hearted killer due to some tragic event in his past. For example, the death of his friends like Sasuke could lead him to abandon his kind - hearted nature. Another theme might be his struggle against the ninja world that has wronged him, where he uses his new - found cold - heartedness as a weapon. Also, his relationship with other characters can be explored in a very different light. For instance, how Hinata would react to a Naruto who has lost his warmth and is just a killing machine. This can create a lot of interesting and complex storylines in the fanfiction world.
Well, it depends on the specific fanfiction. Some fanfic authors might write Naruto as cold - hearted for the sake of creating a unique plot or exploring a darker side of the Naruto universe. However, in the main Naruto series, he is far from cold - hearted. He has a big heart and is always trying to save and protect those around him. So, in most cases in fanfiction, it's an interesting but not - so - true - to - the - original take on his character.
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.
In some fanfiction, Naruto might be depicted as a cold killer, but this goes against his canonical character. In the original Naruto series, he is a warm - hearted and determined ninja who values friendship and peace. However, in the realm of fanfiction, authors can take creative liberties and present a very different version of him.
One common theme is the transformation of Naruto's character. His cold - heartedness often stems from some sort of betrayal or past pain, like being ostracized by the village. This changes his once - warm and friendly nature into a cold, more self - centered one.
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.
In some fanfics, Naruto might be depicted as cold - hearted, but it goes against his canonical character. The original Naruto is known for his warm - heartedness, determination, and his ability to see the good in people. Fanfic authors may take creative liberties for various reasons like exploring different storylines or character arcs, but it's not a common or true - to - the - source representation of Naruto.