He could be a mentor. Given his vast combat experience and his ability to master different techniques, he could guide the young heroes in My Hero Academia. Just like how he was trained by Master Roshi and others, he could pass on his knowledge to the likes of Izuku or Bakugo.
In a My Hero Academia fanfiction, Goku could be a mysterious outsider. He arrives in the world not fully understanding the concept of quirks but still managing to be a force for good. He could be a bit of a wild card, not following the normal rules and procedures of the hero society. His carefree attitude towards life and battle could both annoy and inspire the more structured heroes. His energy - based attacks and his ability to fly without any sort of device would make him a very unique and formidable presence in the world of My Hero Academia.
Goku might also be a catalyst for change. His alien origin and his different power system (ki instead of quirks) could inspire the heroes and scientists in the My Hero Academia world to think differently about power and abilities. He could start a new trend in training methods and power - up strategies. For instance, his gravity training could be something that All Might or other pro - heroes might consider implementing. Also, his friendly rivalry with Vegeta could be translated into a similar relationship with a hero or villain in the My Hero Academia world, driving both sides to improve.
He could be a transfer student. Just like how many characters join UA High, Killua could transfer in with his unique set of skills. He would be the cool and mysterious new guy that everyone is curious about.
Ichigo could be a catalyst for change. His arrival might disrupt the status quo in the hero world. For instance, his different approach to fighting villains, which is more about eliminating threats rather than just subduing them as in My Hero Academia, could start a debate among the heroes about the best way to deal with evil. And his unique powers could inspire new ways of thinking about quirks.
He could start as a naive but powerful character, similar to his early days in Dragon Ball. Then, as he experiences the more complex hero society in MHA, he could learn about teamwork and strategy. Maybe he'd start out thinking he can handle everything alone but then realize the value of his classmates or fellow heroes.
He could be a mentor figure. Goku has a lot of experience in fighting powerful enemies and growing stronger. He could teach the demigods in Percy Jackson's world some new combat techniques.
Well, 'death' could also be personified as a character. It might act as a sort of antagonist, constantly looming over the heroes and causing them to face their mortality. This can add a sense of dread and urgency to the story. Maybe it has the power to take away a character's quirk when they come close to death, which would be a really interesting take in the context of the 'My Hero Academia' universe.
Toph could also be a part of a cross - over team in the fanfiction. She might join forces with some of the heroes in My Hero Academia to take on a powerful villain. Her no - nonsense attitude and combat prowess would make her a great addition to any team - up scenarios, and she could bring a fresh perspective and set of abilities to the battles in the My Hero Academia world.
Goku could be a hero who saves the day. For example, when the Rebels are facing a powerful Sith Lord, Goku shows up and uses his Ultra Instinct to defeat the enemy. His pure - hearted nature would make him a natural ally of the good guys in the Star Wars universe.
Well, Goku's super strength and his ability to constantly power up could be a huge asset in the My Hero Academia fanfiction world. He could be like an otherworldly hero with his Saiyan powers. His Kamehameha wave would be an extremely powerful quirk - like ability. Maybe he could be a visiting hero from another dimension, coming to help out in the battles against the villains in the My Hero Academia universe.
He might be a disruptor. His overpowering strength and different fighting style could shake up the existing power structures in the Naruto universe. He could also be an explorer, coming from his own universe and being curious about the Naruto world, which could lead to many adventures and interactions with different characters.
In a fanfiction, Wolverine could have a complex relationship with the villains. Some villains might be afraid of him because of his reputation and power. But there could be a villain who tries to manipulate Wolverine's past traumas. This could lead to some intense emotional and physical battles, as Wolverine has to fight not only the villain's powers but also his own inner demons.