Well, if Naruto had starfire powers in fanfiction, he could probably use it to enhance his existing jutsu. For example, his Rasengan might be infused with starfire energy, making it more powerful and having additional effects like burning or blinding opponents. Also, it could change his battle strategies as he'd have a new and different type of power to rely on.
Well, Naruto's Rasengan could be combined with Starfire's starbolts. For example, Naruto could use his chakra control to shape Starfire's energy into a Rasengan - like attack.
The origin of Naruto's starfire powers in fanfiction might be due to an experiment. Some rogue ninja or a secret organization could have been conducting experiments with celestial energy. Naruto somehow gets caught in one of these experiments and as a result, he gains the starfire powers. Another possibility is that it's a gift from the stars themselves. Naruto has always been a special character, and the stars, seeing his potential and pure heart, decide to grant him these powers to help him on his journey.
In this fanfiction, the prototype powers could be something like an early form of chakra manipulation that is different from the traditional Naruto world's chakra use. It might be more raw and unrefined, with the potential for new and unique jutsu.
His hidden powers might be the ability to control all five basic nature types without any training. In the original story, Naruto had to work hard to master different nature types. But in a fanfiction, it could be that he has this innate ability which was hidden all along. This would make him extremely powerful and feared by his enemies.
In some fanfictions, Naruto's multiverse powers are portrayed as a way to bring together different versions of himself. Each version has its own set of skills and knowledge. By merging these aspects, he becomes an even more powerful and complex character, able to solve problems that were previously insurmountable.
Imagine a battle scene where Spiderman's agility and quick reflexes allow him to dodge attacks and get close to the enemy. Then, Starfire uses her powers to stun the enemy with a blast of energy. Spiderman can then use his webs to immobilize the stunned foe. Their powers work in a complementary way, with Spiderman's more street - level powers enhancing Starfire's more cosmic - level powers and vice versa.
Their powers could combine in a really cool way. Harry's magic could enhance Starfire's energy blasts. For example, he could cast a spell on her hands that would make her energy blasts more powerful or more accurate. On the other hand, Starfire's superhuman strength could help Harry in physical combat situations. If they were surrounded by enemies, Starfire could use her strength to clear a path while Harry used his magic to hold off any attackers from a distance.
I really like 'Naruto and Starfire: A New Beginning'. In this fanfic, Naruto somehow ends up in Starfire's universe. It shows how he adapts to the new and strange environment. There are some great character interactions, especially between Naruto and Starfire as they learn about each other's cultures and powers. It also has some exciting battle scenes where Naruto uses his jutsus in the new world.
Yes, there might be. There are a vast number of fanfictions out there on various platforms. You can start by looking on popular fanfiction websites like Archive of Our Own or FanFiction.net. Just search for 'Naruto brother of Starfire' and see what pops up.