Harry's character would develop a new sense of self - preservation. In Slytherin, he'd learn that sometimes it's okay to look out for himself first. This doesn't mean he'd become selfish, but he'd be more aware of his own needs. His relationships would also shift. He might have closer bonds with Slytherin students who share his new - found values. He could also start to question some of the Gryffindor ideals he once held so dear, and this internal struggle would shape his character in new and interesting ways.
His character would likely become more calculating. Instead of the impulsive Gryffindor actions, he'd think things through more carefully. For example, when facing challenges like the Triwizard Tournament, he might use his Slytherin traits to find loopholes in the rules rather than just charging in bravely.
If Harry becomes a Phoenix in fanfiction, his character development would be really interesting. He would gain a sense of mystery. People would be in awe of him. He might become more patient, like how Phoenixes are patient in their long lives. He would also have to deal with the loneliness that might come with being a unique creature in the wizarding world.
His character would become more complex. He'd have to struggle with his newfound thirst for blood, which could make him more brooding. He might become more isolated as he tries to hide his vampiric side from his friends. His sense of right and wrong would be challenged as he has to deal with the darker aspects of his new existence.
Harry Potter would grow in different aspects. He'd gain more knowledge about the spiritual realm. His Gryffindor bravery would be put to the test in a whole new context. He might become more solitary as exorcist work can be isolating. But at the same time, he could form new alliances with those in the exorcist community. His experiences would make him more empathetic towards those haunted by spirits.
If Harry Potter becomes a mercenary in fanfiction, his character would develop in several ways. Firstly, he would become more adaptable. In the mercenary world, he'd encounter different cultures, magic systems, and people. He'd have to quickly adjust to new situations. Secondly, he'd become more calculating. Instead of relying on his gut instincts like he did in his battles against Voldemort, he'd need to plan and strategize more carefully. His experiences as a mercenary would also harden him emotionally. He'd see a lot of death and destruction, which would change his once - innocent view of the world. However, deep down, his core of kindness and justice might still be there, just buried under the tough exterior he'd need to survive as a mercenary.
His character would likely become more patient. Since he has all the time in the world, he won't be in a rush to make decisions. He could become a great philosopher of magic, spending years thinking about the deeper meaning of spells and magical abilities.
His character would become more complex. He might start to question his Gryffindor - like instincts and develop a more calculating side. His confidence could take a hit initially as he tries to fit into a house with a different set of values.
He'd become more withdrawn. His usual confidence would be shaken. Instead of being the bold Gryffindor, he'd be more cautious. He might question his place at Hogwarts and in the wizarding world.
He'd be more cunning. In Gryffindor, Harry was brave and impulsive. In Slytherin, he'd learn to think before acting. He might also become more ambitious, not just about defeating Voldemort, but about changing the reputation of Slytherin.
If Harry becomes a house - elf, his character would develop in a way that he becomes more resourceful within the constraints of a house - elf's life. He would have to use his wits to get things done because house - elves have limited magic compared to wizards. Also, his sense of justice would be even stronger. He would be constantly looking for ways to break the chains of the traditional house - elf servitude, maybe by finding loopholes in the ancient laws that bind them.
Harry's character would likely become more hardened. In Mandalore, he'd face different challenges than in the wizarding world. He'd have to be more physically tough, which would make him more confident in his own abilities. His sense of justice would also expand as he learns about the Mandalorian code. He might become more of a lone wolf, relying on his own skills rather than always having his friends by his side as he did in Hogwarts.