In this kind of fanfiction, the other villages could also be Naruto's enemies. If they pose a threat to Konoha or if they have some dark secrets that Naruto, in his cold - hearted state, wants to expose. For example, the Mist Village with its history of the Blood Mist. Naruto could target their leaders or ninja who are involved in unethical practices. Also, any rogue ninja groups that operate outside the law and cause trouble for Konoha could be on Naruto's hit list. He would no longer be the lenient Naruto we know but a cold - hearted killer who doesn't tolerate any threats to his village.
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.
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.
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.
The Akatsuki could be potential enemies. They might see the Mokuton Prodigy as a threat or a valuable asset to capture. Their diverse powers and motives would make for interesting confrontations with the prodigy.
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.
The people who previously neglected Naruto could become his enemies. They might see his new - found power with the Keyblade as a threat.
Potential allies could be his friends like Sasuke. Sasuke, with his sharingan and combat skills, could team up with Naruto in battles against those who fear Naruto's newfound genjutsu power. Enemies might include Orochimaru. Orochimaru is always interested in powerful abilities and would likely see Naruto as a threat to his plans.
Allies would definitely include Naruto's closest friends like Sasuke and Sakura. They would stand by him even with his new identity. From the Dragon Ball world, Goku could be an ally as he has a good relationship with Beerus. Enemies could be those who want to use Naruto's connection to Beerus for their own evil purposes. For example, some rogue ninja groups might try to capture Naruto to bargain with Beerus. Also, any new villains introduced in the fanfiction who are jealous of Naruto's power would be his enemies.
The Hidden Villages could be antagonists. If Naruto turns into an insane killer, the villages would see him as a threat and try to stop him. They might send their best ninjas, like Kakashi or Might Guy, after him.
Bandits could be one type of enemy. They might be after Naruto's supplies or try to capture him for ransom. Another potential enemy could be rogue ninjas who are hiding in the wild. They see Naruto as a threat or an easy target. And then there are the wild beasts that might see Naruto as an intruder in their territory and attack him.
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.