Well, Goku Black could be a powerful antagonist in the RWBY fanfic. His combat skills and powers from the Dragon Ball universe would make him a formidable foe. He could have his own motives, like seeking power in the RWBY world or trying to impose his own sense of order. For example, his ability to use ki blasts could be a new and terrifying threat to the Huntsmen and Huntresses in RWBY.
Goku Black could enter the RWBY fanfic through a portal or some sort of interdimensional rift. Once in the RWBY world, he could start causing chaos. He might target the academies, seeing them as a source of power or a threat to his plans. His unique fighting style, which combines martial arts and ki - based attacks, would be very different from what the RWBY characters are used to. This could lead to some interesting training arcs for the RWBY characters as they try to figure out how to counter his attacks.
One way Goku Black could be incorporated into an RWBY fanfic is by having him be a mysterious figure from another dimension. He might initially be mistaken for an ordinary threat, but as the story progresses, his true power and origin are revealed. He could also interact with the existing villains in RWBY, perhaps forming an alliance or competing with them for control. His Saiyan strength and combat techniques would add a whole new dynamic to the battles in the RWBY fanfic.
Well, Goku's super strength and fighting abilities could make him a powerful ally or a formidable foe in the Naruto world. His ki powers might be seen as a strange new form of chakra. He could also teach the Naruto characters some of his unique fighting techniques, like the Kamehameha wave.
Perhaps Goku would be a traveler from another dimension in the Star Wars fanfiction. He stumbles upon the Star Wars galaxy while exploring different universes. His naivete about the ways of the Star Wars world would be an interesting aspect. He might initially mistake the lightsabers for some sort of Ki - enhanced weapons. His presence would disrupt the power balance as he's so much more powerful than most characters in the normal Star Wars setting, and this could lead to all sorts of new storylines.
Goku Black could be a powerful new threat. His ability to instantaneously move between spaces using his powers would be like a more advanced form of the Shanks' ability to appear suddenly. He could easily target the weak points of the various islands in the One Piece world.
Well, Goku could be a powerful Jedi or Sith in a fanfic. His super strength and fighting skills would make him a force to be reckoned with. He might use his Ki abilities like the Force, and his Saiyan transformations could be seen as a new kind of power-up in the Star Wars world.
In fanfiction, Darth Revan could be a mentor figure to some of the RWBY characters. For instance, he could see potential in Jaune and take him under his wing. He could teach Jaune about strategy and how to use the Force to sense opponents' moves. This would give Jaune a new edge in combat and also create an interesting dynamic between the two, as Jaune has his own moral code which might conflict with Revan's at times.
Well, Bruce Wayne could bring his detective skills. He's like a super detective in his own world. In RWBY, he could help uncover secrets about the Grimm or the various factions. Maybe he'd team up with Team RWBY and use his martial arts skills in combat against the bad guys.
Well, Goku's extreme power level could make him a sort of legend in the Naruto fanfiction world. His Saiyan abilities like the Kamehameha and Super Saiyan forms would be completely foreign to the ninjas. He might be seen as an otherworldly being, and his presence could disrupt the power balance. Maybe he'd come to the Naruto world seeking a new challenge, or perhaps he was accidentally transported there.
Black Agumon could be a summon. Similar to how ninja summon animals, a character in the Naruto world discovers a way to summon Black Agumon. Its digital world powers would make it a very unique and powerful summon, changing the dynamics of battles.
He could be integrated as a powerful enemy at first. He might target the academies because he sees them as places that are trying to control and limit power, which goes against his own philosophy. However, as the story progresses, he could have a change of heart after seeing the selfless acts of the RWBY characters. He could then use his powers to help them against a common enemy like Salem.
Goku Black could potentially enter the High School DxD world through a dimensional rift or some sort of magical accident. Once there, his Saiyan pride and his dark motives (from his own story) could lead to him either trying to take over the various factions in the DxD world or simply looking for a worthy opponent. He might interact with the main characters like Issei, perhaps seeing him as a target to prove his superiority or a potential ally in his own schemes.