Well, in this kind of fanfiction, it might happen through some sort of cross - dimensional magic. Maybe there's a rift between the Naruto universe and the Dragon Ball universe that allows Naruto to gain the power of a Super Saiyan God. It could also be the result of a powerful wish made by a god - like character who decides to give Naruto this new form for the sake of saving his own universe or something like that.
One possibility is that Naruto is sent on a special quest by some unknown entity. During this quest, he encounters the same kind of divine energy that is required to transform into a Super Saiyan God in the Dragon Ball world. He then has to master this energy, which could be extremely difficult considering his different chakra - based power system. But through his determination and unique ninja skills, he somehow manages to merge the Saiyan God energy with his own chakra, thus achieving this incredible transformation.
It could also be due to a strange prophecy. In both the Naruto and Dragon Ball worlds, prophecies play a big role. There could be a prophecy that a hero from one world would gain the powers of the other to defeat a common enemy. Naruto, being the hero of his world, is chosen and through some spiritual or magical transformation, he becomes a Super Saiyan.
Well, he would probably become extremely powerful. He could gain the ability to transform into a Super Saiyan, which would boost his strength, speed, and energy projection to incredible levels. His ninja skills combined with Saiyan power would make him nearly unbeatable in battles.
Well, if Naruto goes Super Saiyan 3 in a fanfiction, he would likely gain an insane amount of power. His physical abilities would skyrocket. He could move at incredible speeds, and his strength might be enough to shatter mountains. His chakra would probably combine with the Saiyan power in some unique way, creating new and powerful jutsu.
Well, one way could be through some sort of magical cross - over event. Maybe the gods in the Percy Jackson universe notice Naruto's great power and determination from his own world. They decide to bestow god - like powers on him, perhaps seeing him as a worthy addition to their pantheon. Another possibility is that Naruto somehow stumbles into a magical portal that connects his world to the Percy Jackson world and there, he undertakes a great quest that earns him god - hood.
If Naruto becomes super IQ in the fanfiction, he could potentially become a master of multiple fields. He could be an excellent diplomat, using his intelligence to negotiate treaties and alliances. He would also be a great inventor, creating new tools and weapons for the ninja world. His friends might be a bit in awe of his newfound intelligence at first, but they would soon realize that he's still the same Naruto at heart, just with a much sharper mind.
Well, he might gain extraordinary powers. Maybe he can control all the elements in a much more powerful way than before. For example, his fire jutsu could be so strong that it can burn through any defense easily.
Naruto could also face challenges from other powerful beings in the universe. Since he is now a God of Destruction, he might attract the attention of those who oppose such a powerful entity. He would have to fight battles not just with his physical strength but also with his wits to maintain his position and the balance he is supposed to uphold.
Well, he might use his ninja skills to catch Pokemon in unique ways. For example, he could use his shadow clone jutsu to surround a Pokemon and catch it more easily. His ability to endure tough situations would also make him a great Pokemon trainer in this fanfic scenario.
Well, one way could be through some kind of strange jutsu gone wrong. Maybe Naruto was experimenting with a new type of chakra manipulation and it accidentally combined with some sort of mutagenic energy, similar to what created the Hulk. And then, poof! He starts turning into the Hulk whenever he gets angry. Another possibility is that he encounters a villain who has the power to transform others and decides to use Naruto as his guinea pig to create a super - strong and uncontrollable Naruto - Hulk hybrid.
Well, in fanfiction, anything is possible. Maybe Naruto gets transported to the Sekirei world through some sort of magic or a strange portal. This could be the start of his journey to become a Sekirei. It could also be due to a curse or a wish gone wrong that transforms him into a Sekirei - like form.