Well, Goku Black could be the more dominant character. His dark nature gives him a different kind of power. He doesn't have the same moral constraints as Goku. This could allow him to make more ruthless and effective decisions in battle. He might be able to outmaneuver Goku if he plays his cards right.
It could be Goku. He has always been the main hero in the Dragon Ball series. His unwavering sense of justice and his eagerness to protect the Earth would likely make him take the lead in most situations. Also, his combat experience and his ability to quickly adapt to new opponents would give him an edge in any interaction with Cell.
Raditz would likely be the more dominant character at first. He's older, more experienced, and has a higher power level. He could easily overpower Kid Goku physically.
I think Zeno would be a really tough opponent. Zeno has the power to erase entire universes, and a Goku and Goku Black fusion, despite being extremely powerful, would have a hard time against such a being with god - like powers.
A Goku and Goku Black fusion in fanfiction could be really exciting. The fusion would inherit Goku's love for fighting and getting stronger, but also Goku Black's ambition. Their combined ki could be a new type of energy that no one has ever seen before. This new fused form might also have new transformations or abilities. For example, it could combine Goku's Super Saiyan forms with Goku Black's Rose form in unexpected ways. It could change the power balance in the Dragon Ball world and open up all sorts of new storylines, like teaming up with other characters to take on new threats or even having internal struggles between the two personalities within the fusion.
In fanfiction, if Goku Black fused with Goku, it could potentially create an extremely powerful being. This new entity might have a mix of Goku's pure heart and Goku Black's more sinister motives, which could lead to a complex internal struggle. Their combined power could be off the charts, perhaps strong enough to defeat any foe in the Dragon Ball universe. However, it could also cause chaos as their different personalities clash within the fused form.
Well, in fanfiction, if Goku Black fuses with Goku, it could result in a super powerful being. Their combined powers might create a new form with an extremely high power level. This new entity could have a mix of Goku Black's dark and devious nature with Goku's pure-hearted heroism, leading to an internal struggle within the fused form.
Sasuke could also oppose Black Goku. With his Sharingan and Rinnegan, Sasuke has a wide range of powerful abilities. He is also very intelligent and strategic. Sasuke would likely see Black Goku as a threat to the balance of power in the Naruto universe and would step in to fight him, especially if it involved protecting his friends or the ninja world in general.
In a Goku Naruto crossover, both characters have their own strengths. Goku's physical strength and energy attacks are off the charts. His ability to instantly teleport and sense ki gives him an advantage in combat. Naruto, though, has a unique power system. His connection to the Nine - Tails and his ability to use different types of chakra make him a force to be reckoned with. If we consider a battle, Goku's power might seem greater on the surface. But Naruto has the advantage of being able to surprise his opponents with his ninjutsu and clones. Also, Naruto has a strong willpower that has allowed him to overcome many tough situations, which could play a role in a fight against Goku.
The story could start with Goku being pushed to his limits by Goku Black's attacks. But then, he remembers his training with the Kai's and how they taught him to focus his energy in a more efficient way. He then uses this knowledge to create a more powerful Kamehameha that breaks through Goku Black's defenses and kills him.
If Goku Black fuses with Goku in fanfiction, the story would progress in a complex way. The fused form might go on a journey to understand itself. Since it has two very different personalities combined, it would face a lot of internal conflict. This could be used to explore themes like identity and the struggle between good and evil. Externally, the fused Goku could attract new enemies who see it as a threat to their power or plans.