In this fanfiction scenario, Naruto could potentially use new and untested jutsu. He might draw on the power of his nine - tailed fox in a completely different way. Maybe he'd combine Sage Mode with some secret Uzumaki clan technique he discovers during the fight.
Maybe an ancient evil ninja who was sealed away long ago but has now been released. This antagonist could have powers that nullify any communication or summoning jutsu, forcing Naruto to fight alone. He would be extremely powerful and know many forgotten and deadly jutsu.
In a 'naruto fights alone fanfiction', it could be that Naruto is on a mission in a foreign land where he has no support. The local ninjas are all against him for some reason. He has to use his Nine - Tails chakra in a more discreet way as he can't afford to go all - out and draw too much attention. He might befriend some local animals or spirits who help him in a more indirect way, like giving him information about the enemies' weaknesses.
In such a fanfiction, Naruto could potentially win by using his new Sage of Six Paths powers to their fullest. He might be able to overpower Madara's Rinnegan abilities. For example, Naruto could use his massive chakra reserves to create countless shadow clones and overwhelm Madara in a battle of attrition.
Well, Harry is a very determined and resourceful wizard. He has overcome many powerful enemies in his own world. But Kaguya is on a whole different level of power. She has the power to create dimensions and manipulate time. Harry would need to be extremely clever and use his magic in ways he's never done before. For example, he could combine different spells to create a super - spell. But even then, Kaguya's raw power might be too much for him to handle. So, in most cases, Kaguya would likely win, but with Harry's unpredictability, there's always a small chance he could pull off a victory.
The fanfiction could start with Harry being magically transported to Kaguya's world. He'd be confused at first but quickly realize he has to fight to survive. Harry's wand would be his main weapon. He might learn some new spells during the fight, perhaps a spell that can nullify Kaguya's ability to freeze time. As the fight progresses, both characters would start to respect each other's power, leading to an unexpected alliance at the end.
Naruto could potentially use a new form of the Nine - Tails Chakra Mode. Maybe he combines it with his Sage Mode in a more seamless way than ever before. This would give him enhanced strength, speed, and the ability to sense danger more acutely.
One of the most exciting scenes could be when Naruto first unleashes his Nine - Tails chakra in a full - blown rage. The red chakra would surround him, his eyes would turn into slits, and he would let out a powerful roar. As he charges into the army, the soldiers would be both terrified and in awe of his power.
In a Naruto fanfiction where he fights an army alone, he could win through his vast array of jutsu. His Shadow Clone Jutsu could be used to create multiple decoys, confusing the enemy. Also, his Rasengan, a powerful and concentrated chakra attack, could take out many foes at once. His Nine - Tails chakra might also give him a huge boost in power and endurance, allowing him to keep fighting against overwhelming odds.
Well, Naruto could change Kaguya in the fanfiction by introducing her to the concept of redemption. Given his own journey of facing his inner demons and coming out stronger, he might convince Kaguya that she can atone for her past sins. He may take her on a journey through the ninja world, showing her how people have rebuilt and thrived despite the chaos she once caused. This could make her re - evaluate her actions and change her perspective on the world and her place in it.