There's a chance that it could be an old and powerful wizard from a far - off land. This wizard could have unique magical abilities and training methods that are not known in the British wizarding world. Harry would be exposed to a whole new set of magic and training styles, which would make the fanfiction more interesting.
Well, it could be that Harry is training for a big wizarding tournament. He might be learning new spells and combat techniques from a mysterious and strict mentor. Maybe he has to endure physical and mental challenges that test his limits.
One of the major changes could be in his relationships. As he gets more involved in the training, he may drift away from some of his old friends who don't understand his new focus. At the same time, he might form closer bonds with those who are also involved in the training or who support his growth. His self - identity could also shift as he starts to define himself more by his new skills and abilities gained from the training rather than just his past experiences.
In such a fanfiction, Harry could face many challenges during the intensive training. This would test his limits and make him more resilient. Maybe he'll learn some ancient or forgotten magic, which could change the way he approaches future battles. Also, his relationships with other characters might evolve as he becomes more of a force to be reckoned with through this training.
It could be Sirius Black. Sirius was a very powerful wizard and he had a special bond with Harry. He could have come back in some way to train Harry in some unique magical skills, like how to transform into a more powerful animagus form.
Kakashi could be a likely trainer. He's experienced and has a mysterious side to him. He could use his knowledge of human nature and ninja skills to train Naruto in seduction. Another possibility is Tsunade. As a strong female character, she could teach Naruto different aspects of seduction, especially when it comes to dealing with the opposite sex.
He could meet an experienced trainer who becomes his mentor. This mentor could teach Ash some advanced Pokémon training techniques that he hasn't known before.
It could be Kakashi. He has a lot of knowledge and skills that he could pass on to Naruto more intensively. Maybe he takes Naruto on a long - term mission where they train on the go. Kakashi could focus on improving Naruto's Sharingan - like observational skills and help him develop new strategies for combat.
Well, he may face new challenges in the trainer school. There could be tough exams on Pokémon knowledge and battle strategies. He might struggle with some theoretical parts but shine in the practical battle tests.
In the 'Harry goes through the veil fanfiction', Harry may face a great deal of danger. The veil is often associated with death in the wizarding world. So, perhaps he has to fight off dark forces that lurk on the other side. He might also have to find a way back to the living world, which could involve solving puzzles or making difficult choices. There could be a new set of magical rules there that he has to learn quickly in order to survive.
There's a chance it could be a powerful house - elf. House - elves are known for their own brand of magic, and one particularly rebellious or enlightened house - elf could decide to train Harry in magic that is more about stealth and quick - thinking. After all, house - elves have to be very sneaky to avoid detection by their masters most of the time, and this kind of skill could be very useful for Harry in his battles against Voldemort.