In the Harry Potter series, there were many cases where Harry Potter was punished. For example, in the first book, Professor McGonagall had to deduct 50 points from each of them as punishment for being reported by Draco to be in the corridor after curfew because they had gone to find Hagrid. In the third Prisoner of Azkaban, Harry broke the rule that first years were not allowed to use broomsticks alone, but he got away with it and joined the Quidditch team as a first year. He was also often confiscated for breaking school rules, such as Professor McGonagall's Firebolt in his third year (though it was later returned). In addition, breaking the school rules could result in the deduction of House points. As the "troublemaker" of Gryffindor House, Harry often deducted points for causing trouble. There was also the punishment of "staying in school", which meant that they could not return to the dormitory after class or during the break period. Instead, they had to complete other punishment tasks arranged by the professor. Harry Potter and the Goblet of Fire was not enough. Everyone, please click to read the novel!
Harry would likely be defiant at first. He has a strong sense of justice and would not easily submit to Voldemort's punishments. For example, if Voldemort uses the Cruciatus Curse, Harry would probably try to resist the pain and not show weakness.
Well, Harry could marry one of the veelas. Given their beauty and allure, it would add an interesting dynamic to the story. Their relationship could involve Harry having to deal with the jealousy of other wizards and also the cultural differences of the veelas. Or he could marry a descendant of one of the founders of Hogwarts. This would tie in a lot of Hogwarts history into their relationship, and their wedding could be a grand event that unites different factions within the wizarding community who have ties to the founders.
Maybe Dumbledore, if he were still alive in the fanfiction. Dumbledore was highly respected and had a great influence. Knighting Harry would be a way for him to publicly recognize Harry's achievements and heroism on a grand scale.
One possible scenario could be that Voldemort punishes Harry Potter by using the Cruciatus Curse on him. In the wizarding world, this is a very cruel form of torture. Another situation might be that Voldemort imprisons Harry in a dark and desolate place, like the dungeons of Malfoy Manor. He could also force Harry to watch as he harms his friends, which would be a psychological form of punishment for Harry, who values his friends highly.
Snape could also be a possibility. If Harry did something that Snape considered a serious offense in Potions class, like using an ingredient in the wrong way that could have caused an explosion, Snape might send a howler to scold him. However, it would probably also be filled with his usual sarcasm and dislike for Harry.
It could be Hagrid. Hagrid is always looking out for Harry and giving him things. He might come across this special trunk during one of his travels in the Forbidden Forest or in some wizarding market and think it would be perfect for Harry.
It could be Dumbledore. Dumbledore is always full of surprises and he might give Harry the staff as a last - resort weapon to fight against Voldemort. He could have been secretly researching the staff and its powers and decided that Harry was the only one who could wield it properly.
Hermione Granger is a very common character. Since she is Harry's best friend, she would likely be there to help him understand and control his new superpowers. She might research in the library to find out how these powers came about and how to use them effectively. Ron Weasley is also common. He would probably be both in awe and a bit jealous of Harry's new powers at first but would still support him in the end.
He could meet other young wizards and witches who are also working summer jobs. Maybe some from other wizarding schools.
It could be Voldemort. He might use hypnosis as a new way to get to Harry, trying to make him a weapon against the Order of the Phoenix. Another possibility is a new dark wizard who wants to make a name for himself by controlling Harry Potter.