In this fanfiction scenario, Vegeta's power might manifest in Naruto's ki control. Since Vegeta is from the Dragon Ball universe where ki is important, Naruto could start to sense and manipulate a similar type of energy. He could use this newfound energy for things like enhanced speed, allowing him to move so fast that he appears as a blur to his enemies. Also, it could be used for energy blasts, although Naruto would have to learn how to shape and control them in his own ninja - like way.
Vegeta's power could also show up in Naruto's combat instincts. Vegeta is a highly skilled warrior with years of battle experience. When sealed in Naruto, his battle - hardened instincts could start to influence Naruto. So, Naruto might start making more strategic decisions during fights. Instead of just relying on his shadow clones all the time, he could analyze his opponents' weaknesses more quickly and strike at their most vulnerable points, like Vegeta would do in his battles in the Dragon Ball series.
Sakura might be initially shocked and worried. She'd be concerned about how this new entity within Naruto could affect his health and stability. But she'd also be curious to see if this could give them an edge in future battles.
In a fanfic, Naruto might power up by having a spiritual awakening. He could connect with the spirits of past Hokages in a deeper way, gaining their knowledge and some of their power. This could enhance his existing jutsu and give him new abilities. Vegeta could power up if he were to face a near - death experience against Naruto. This could trigger a hidden potential within him, like a new type of Super Saiyan form that has unique abilities. He could also fuse with another Saiyan (if there were another Saiyan available in the fanfic's scenario) to create an even more powerful being.
It would completely transform his power level. Consider that each bijuu has its own distinct set of skills and chakra reserves. Naruto would be like a living, breathing nuclear reactor of chakra. His ability to heal himself might be enhanced, as some bijuu are associated with life - force. He could also potentially communicate with all the bijuu spirits, getting their insights and battle strategies. This new - found power would not only make him stronger in direct combat but also give him an edge in terms of strategy and knowledge. He could become a sort of protector of the entire ninja world, with the combined might of all the bijuu at his disposal.
Well, Naruto might become more mysterious. Since Gaster is an unknown and rather enigmatic entity, Naruto could start having strange thoughts or powers that he doesn't fully understand at first. He might seem more withdrawn as he tries to figure out what's going on inside him, and his normal cheerful and straightforward personality could be clouded by the presence of Gaster.
It really depends on the context. If it's a physical strength battle, Vegeta might have the upper hand initially due to his Saiyan strength. But Naruto has incredible stamina and the ability to tap into the Nine - Tails' power. So in a long - drawn - out fight, Naruto could potentially outlast Vegeta.
Some fanfictions might depict Naruto's lightning power as being connected to his emotions. When he gets angry or determined, the lightning power becomes more intense. He could use it to charge up his other jutsu, like his Rasengan. By infusing the Rasengan with lightning, it becomes a more powerful and deadly attack, with the added electrical damage that can disrupt an opponent's chakra flow.
The power level would be insanely high. Naruto already has access to a huge amount of chakra, especially in his later forms like Six Paths Sage Mode. Vegeta, on the other hand, has his Super Saiyan forms which multiply his power exponentially. When fused, they would likely have a power level that could easily rival some of the most powerful beings in both universes.
With his enemies, it would be a whole different story. They might be more cautious about attacking Naruto. Some might even try to find a way to use the god sealed in him for their own purposes. And Naruto's relationship with the hidden villages could also change. They might see him as a potential threat or a very valuable asset.
One way Naruto could be related to Vegeta in fanfiction is through a crossover of universes. Maybe a powerful magic or some sort of interdimensional rift brings them together. Then they could discover that they are related through some ancient prophecy or a long - lost family connection that spans across different anime worlds.
Often, Vegeta becomes more in touch with his emotions. He starts to care about things other than just fighting, like his family with Bulma. He may show more love and protectiveness towards her and their child.