Harry would change the House of Potter by instilling values of courage and loyalty in a more hands - on way. He'd be a role model for the students, showing them that it's okay to make mistakes as long as you learn from them. He might also introduce new traditions that are more about helping others and less about competition. For example, he could start a program where the older students tutor the younger ones not just in academics but also in life skills.
He might start by promoting fairness and equality within Slytherin. In the original series, Slytherin is often associated with pure - blood supremacy. Harry, as head, could break that stereotype. He could encourage students from all backgrounds to work together and support one another, changing the cut - throat competition within the house to a more collaborative environment.
As head of house, Harry might struggle with the administrative tasks. He's not used to paperwork and bureaucracy. He also has to ensure the safety of the students during dangerous times, which is no easy feat. The House might attract unwanted attention from dark forces because of his fame. So he has to be extra vigilant in protecting the students. Additionally, he needs to find a way to inspire the students who may be intimidated by his heroic status rather than be motivated by it.
Well, it could make Slytherin more strict. Draco has his own ideas about purity and power from his family upbringing. He might enforce more traditional Slytherin values, like ambition above all. This could lead to more competition within the house, as students strive to meet his high standards.
It changes the power balance. Instead of the houses competing, they support each other. For instance, in battles against dark forces, the combined strength of all houses makes them more formidable.
Luna Lovegood could be an interesting head of Ravenclaw. She has such a unique and creative way of thinking. Her love for all things strange and wonderful would make her a very different kind of head. She would encourage students to explore ideas that are outside the box and not be afraid to be themselves. For example, she might introduce new classes on magical creatures that are not commonly studied, like the Crumple - Horned Snorkack.
The house elf might be very grateful. Harry is known for his kindness, so the elf could see this as a chance for a better life. It might immediately start serving Harry with great enthusiasm, believing that Harry will be a fair and good master.
He might become more sneaky and calculating. Since he's a thief now, he would have to be good at hiding his actions and planning his 'heists'. His moral compass might also shift a bit as stealing isn't exactly an ethical behavior in the normal wizarding world.
Perhaps it's a former student who was never fully accepted in any of the four houses. They created the fifth house as a place for those who didn't fit in. This person would be very empathetic towards Harry's situation, having been through a similar experience. They would be strict but fair, teaching Harry and his housemates that being different is a strength, not a weakness.
The perception of Harry would be turned upside down. In the original series, he is the symbol of good and the one who defeats Voldemort. But in this fanfiction, he is the one causing harm, which makes readers question everything they thought they knew about his character. His motives, actions, and relationships would all be seen in a new and disturbing light.
His life might become more self - contained. He'd have to rely more on himself without the big support system of Hogwarts. He might become more resourceful, like finding new ways to cook with limited space and resources in the tiny house.