It could be a rogue ninja who has been secretly building power while Naruto was away. This rogue ninja might have a vendetta against Konoha and sees Naruto's return as a challenge to his plans. So he directly confronts Naruto to prove his own strength.
Perhaps in the 'naruto returns stronger fanfiction', Naruto returns with enhanced physical abilities. He could have trained in a special place that increased his strength, speed, and stamina exponentially. For example, he might have found a way to tap into a new source of chakra that is much more powerful than the normal one. This would make his attacks more devastating and his defenses impenetrable.
Well, it could be that Naruto has found a way to tap into some ancient and forgotten power source during his time away. So when he comes back to Konoha, he's not only physically stronger but also has a deeper understanding of chakra and how to manipulate it. He might start by showing off his new skills to his old friends like Sasuke and Sakura. And then, he uses his strength to improve Konoha's defenses, such as creating new barriers around the village using his enhanced chakra control.
Here are some recommendations for novels about the protagonist returning to Earth after becoming stronger:
1. [Two-Dimensional Weapon System: The protagonist is brought into another world by the system and can only return to Earth after becoming stronger.]
2. [The Immortal Emperor returns to be a nanny: The protagonist, the peerless Immortal Venerable, has been reborn and returned to Earth to protect his family with greater strength.]
3. The protagonist Qin Zheng was reborn on Earth and had to protect his family and the city with his powerful abilities.
4. " The Earth Leading the Way Party ": The story of the protagonist, Chen Zong, who transmigrated from Earth to another world and became stronger before returning to Earth.
5. " Great Qin: The entire nation ascends to Earth!" The protagonist Zhao Wu transmigrated to another world and became the first emperor of Great Qin. Then, he led the entire Great Qin Empire to ascend to Earth.
6. " The Ancient Human Emperor ": The main character, Tang Yitian, was the last descendant of the Ancient Human Emperor. He worked hard to return to Earth, but was killed by the Primordial Divine Tablet when he passed through space. He was accidentally reborn to 100,000 years in the future.
7. " I, who can travel and break through, return to Earth to show my divinity ": Ye Yingjie obtained the ability of the Kunlun mirror and could travel between Earth and the Dou Qi continent. In order to become stronger, he traveled in the other world and finally returned to Earth.
8. " King of the City's Medical Soldier ": The main character, the super soldier king Qin Zhao, had his soul separated from his main body. His soul traveled through another world to cultivate for 300 years and finally became a supreme emperor. As for his main body, he remained on Earth, becoming a soulless fool who was ridiculed and teased by others. In the end, the Venerable Overlord's soul returned to Earth and returned to his main body to carry out his revenge plan.
These novels all have plots about the protagonist returning to Earth after becoming stronger. You can choose to read according to your own interests.
One reason could be Naruto's unwavering determination. He has always been able to push past his limits. In many battles, his willpower has been a key factor in his victory. Another could be his unique chakra nature and the amount of chakra he has at his disposal. Naruto has a vast reserve of chakra, which gives him an edge in long - drawn battles. Also, his ability to form strong bonds with others might contribute. These bonds could potentially unlock new powers or give him the strength to fight against Kaguya.
In some fanfictions, Naruto might return to Konoha to a cold reception because the villagers still hold grudges from his past. Maybe they haven't fully accepted his power or the chaos he sometimes brought. For example, they could be afraid of his Nine - Tails power flaring up again and causing destruction.
Naruto is stronger in fanfiction because of his ability to connect with others. He has made friends all over the ninja world. This network of friends often provides him with support in battles, whether it's intel or actual combat help. Also, his training under Jiraiya was very comprehensive. Jiraiya taught him not only combat skills but also how to be a better person. This made Naruto grow both physically and mentally. And compared to Sasuke, Naruto seems to be more adaptable to different fighting styles in fanfiction, which gives him an edge in combat.
In fanfiction, it's possible for Naruto to be stronger than Goku. Fanfic writers often tweak the power levels and rules of the characters' universes. For example, if the fanfic writer decides to nerf Goku's Saiyan abilities while enhancing Naruto's Sage Mode and all his ninja skills to an extreme level, Naruto could end up being stronger.
Well, it depends on the specific fanfiction. There are various interpretations out there. Some fanfictions focus on Naruto's growth after the original series and give him abilities like super - charged chakra control or the ability to nullify Madara's strongest jutsu. However, in the original canon, Madara is an extremely powerful opponent. But in fanfiction, the rules can be bent to make Naruto stronger.