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.
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.
Well, it could be about Naruto coming back to Konoha with some new powers related to the golden fox. Maybe he uses these powers to protect the village from a new threat.
Well, Naruto's friends and comrades from his past adventures are likely to be in it. But also, there could be some spiritual or mythical characters related to the concept of the golden fox. For example, there might be an old sage who knows the secrets of the golden fox and can guide Naruto on how to use its power properly. There could also be other villages' representatives who come to Konoha to see this 'Naruto with the golden fox' phenomenon and see if it poses a threat or an opportunity for their own villages.
Well, perhaps Naruto comes back with some super - strong new jutsu that he learned during his absence. He might show off his new power to his old friends and foes alike, leaving everyone in awe.
Perhaps it's an old enemy who has somehow managed to come back stronger. Maybe someone from Orochimaru's old experiments that went wrong, but instead of dying, they gained some dark and powerful abilities. They see Naruto's return as a threat to their plans of world domination, so they target Konoha first. They might be able to control dark chakra in a way that no one has seen before, and use it to create chaos and destruction. They could also have some minions who are equally as powerful and loyal to them, making them a formidable foe for Naruto and Konoha.
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, he might train with new jutsus. For example, he could learn some powerful wind - style techniques. Then on his return to Konoha, he may face challenges like dealing with the villagers' reactions. Maybe some still don't trust him fully even after his training.
Well, in the 'naruto trains and returns to konoha fanfic', Naruto is the central figure. For his training, he could meet some new characters who are experts in certain ninja arts. But in Konoha, all his old comrades will be there. Shikamaru, who is known for his intelligence, might be involved in planning something related to Naruto's return. Ino could be there too, perhaps using her mind - related jutsus to help in some way. And of course, the old sages or elders of Konoha would also be present to assess Naruto's growth and the impact of his return on the village.