In 'harry is an apprentice fanfiction', apart from Harry, there might be other apprentices too. They could be his friends or rivals during his apprenticeship. Also, we can't rule out the appearance of some of the main antagonists from the original series, as they might try to interfere with Harry's apprenticeship journey.
Another possible main character could be a new villain. Since Harry is in a new role as an apprentice, there could be someone who wants to steal the secrets of Ollivander's wand - making. This villain could be a dark wizard or a rogue wizard who has his own motives for wanting to control the wand - making process. Harry would then have to protect Ollivander and the shop from this threat.
Obviously, Naruto and Hayate would be the main characters. Naruto is the protagonist who will be learning from Hayate.
Obviously, Naruto and Hiruzen would be the main characters. Naruto as the apprentice and Hiruzen as the mentor.
Obviously, Naruto and Anko would be the main characters. Naruto, the energetic and determined ninja, and Anko, the somewhat eccentric and skilled kunoichi.
Another possible candidate could be Tom Riddle before he fully became Voldemort. He was already exploring the darkest corners of magic at a young age. The idea of the Sith and their power might attract him. He could see the Sith as a means to an end in his quest for immortality and ultimate power. As a Sith apprentice, he could combine the knowledge of the Dark Side of the Force with his own wizarding knowledge, creating a truly formidable and terrifying entity.
It's hard to say. Harry has a natural talent and courage, which could help him succeed. But Draco is well - versed in the pure - blood magic traditions and might have an edge in some aspects. Snape might be tougher on Harry due to their past, but that could also make Harry more determined. So it could really go either way depending on how the story is written.
Well, obviously Harry Potter himself is a common character. And his mentor, who could be an original character created by the fanfiction author or an existing character from the wizarding world like Albus Dumbledore in a different role as a more hands - on master.
Anko might also be involved in the story. She has her own unique relationship with Yugao and could potentially interact with Naruto. Maybe she gives Naruto some tough love or challenges him in a way that Yugao's teaching methods don't cover. And of course, Iruka sensei could also show up to check on Naruto's progress and have some interactions with both Naruto and Yugao.
Obviously, Harry would be the main character. Since it's about him being a Saiyan. And I think some of his friends from the Harry Potter series might also be important characters, like Hermione and Ron. They could react to Harry's new Saiyan identity in different ways.
The younger students at Hogwarts are quite likely to read Harry Potter fanfiction. They are at an age where they are really into the wizarding world and would be curious about different interpretations. Students like Colin Creevey, who is a big fan of Harry, might be eager to read fan - created stories about his hero. Also, the members of Dumbledore's Army, such as Luna Lovegood and Neville Longbottom, seem like the types who would be open to exploring fanfiction.