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.
It could be insanely powerful. Goku already has incredible power levels, and Goku Black is no slouch either. When they fuse, it's like combining two nuclear reactors. Their power could be so great that they could effortlessly destroy planets just by flexing their newfound power. They might be able to reach Super Saiyan forms that are far beyond what we've seen in the official series, with power levels that are basically off the scale.
Loki would also be a difficult adversary. He's very cunning and could use his tricks and illusions to try and outwit Goku. Goku would need to rely on his senses and ki to see through Loki's deceptions.
The fusion of Goku Black and Zamasu in the manga is quite spectacular. It combines their powers and traits, making for an imposing foe. The visuals and story development around this fusion are really exciting.
Well, it could be super powerful. The fusion might have Goku's Saiyan strength and ability to transform into Super Saiyan forms, combined with Naruto's ninja skills and chakra control. It could fly around with the speed of a Saiyan and use Rasengan - like attacks with the power of a Kamehameha. Just imagine a character with the orange gi and a headband.
In a Naruto - Goku fusion, there could be a new form of energy manipulation. Goku manipulates ki, and Naruto uses chakra. They might create a hybrid energy that has the best of both worlds. This energy could be used for long - range attacks like Goku's energy blasts and also for close - combat like Naruto's Rasengan. Also, the fusion could have enhanced senses, borrowing from Goku's Saiyan senses and Naruto's ninja training.
In fanfiction, a Naruto and Goku fusion could be extremely powerful. They both have unique abilities. Naruto has his ninja skills like shadow clones and Rasengan, while Goku has his Super Saiyan forms and Kamehameha. The fusion might combine Naruto's strategic thinking as a ninja with Goku's straightforward combat style. It could result in a character who can quickly assess a situation like Naruto and then attack with overwhelming power like Goku.
I don't think so. God Fusion Goku is a fictional character created within the realm of certain fictional works.
One interesting fanfiction could be about Goku and Black Goku teaming up against an even greater threat from another universe. In this story, they might initially be at odds but gradually learn to work together, using their unique abilities to save the multiverse.
The plot could involve Goku and Goku Black fusing accidentally. Maybe due to some strange energy anomaly. And then they have to figure out how to control this new form. They might initially be feared by their friends because of Goku Black's reputation, but then they prove that they are on the side of good by using their new powers to protect the Earth from an impending threat that no one else could handle.