If Harry was reborn as Tsuna, his personality would change in several ways. Harry was always a bit of an outsider in the Muggle world, but he had a core group of friends at Hogwarts. Tsuna, on the other hand, has a larger family dynamic to deal with. So Harry might become more family - oriented. Also, while Harry was used to a more structured magical education, in the KHR world, he'd have to adapt to a more chaotic and unorthodox way of learning about his powers. This could make him more flexible in his thinking and less reliant on set rules, which was something he was used to in the wizarding world.
He'd probably be more timid at first. Tsuna is known for being a bit of a wimp in the beginning, and even though Harry has his own insecurities, being in a new world and a new body might make him even more hesitant. But as he gets used to things, his brave side from his past life would start to show more. He'd still have that sense of justice and a willingness to protect his friends, just like he did in the Harry Potter world.
Well, initially, Harry as Tsuna would likely be more reserved. In the Harry Potter series, Harry was often thrust into the spotlight due to his status as 'the boy who lived'. In the KHR world as Tsuna, he might try to avoid the attention at first. However, his loyalty and determination would remain. His experience with facing Voldemort would give him a deeper sense of purpose when it comes to protecting his new friends and family in the KHR universe. And over time, as he grows into his role as Tsuna, he would blend his old Harry Potter - like qualities with the growth and development that Tsuna goes through in the original story, creating a more complex and interesting character.
Naruto might become a bit more reserved at first. Since Tsuna's world is different from Naruto's, he'd have to adapt. But his core of being kind - hearted and determined would remain. He might be more cautious as Tsuna initially isn't as bold as Naruto was in his own world.
Loki's mischievous nature would definitely make Harry more of a prankster. Instead of just being the Boy Who Lived, he'd be the Boy Who Pranked. He might play tricks on Malfoy and his cronies more often and in more elaborate ways.
His confidence would still be there but might be a bit more subdued as he adjusts to the new world. He's used to being a big shot among demigods, but in Hogwarts, he has to start from scratch.
He might become more outgoing. In the Naruto world, the culture is different from the rather formal and often secluded wizarding world. Harry would be exposed to a more boisterous and open - minded society, so he could become more extroverted and less reserved.
Harry's sense of justice would still be there but might be expressed differently. As Jon Snow, he'd be more likely to take matters into his own hands in a more direct way. For instance, instead of relying on the Ministry of Magic's laws like he did in the wizarding world, he'd be more of a lone wolf in Westeros, making his own decisions on what's right and wrong. He'd also probably be more reserved in showing his emotions, as Jon Snow was not one to wear his heart on his sleeve.
His personality would be more aggressive. Yautja are hunters, and growing up with them, Harry would adopt their aggressive nature. He would be more direct in his actions and less likely to hesitate.
He would become more rebellious. Harry has always had a bit of a rebellious streak in the original series, but as a pirate, it would be amplified. He'd be more likely to question authority and do things his own way without waiting for permission.
If Harry Potter was raised by Natsu, his personality would change drastically. Natsu is a very passionate and hot - tempered character. Harry would be influenced by this passion and would be more driven in his pursuits. He would no longer be the meek boy who was bullied by the Dursleys at the start. Instead, he would be more confident and assertive. His sense of justice would also be more like Natsu's, which is more about immediate action rather than following a set of bureaucratic procedures. He would probably have a stronger sense of loyalty towards his friends as well, because Natsu values friendship above all else and would instill this value in Harry.
His personality might become more reserved. Growing up with a Shinigami would expose him to different values than the normal wizarding ones. He might not be as quick to trust or be as carefree as in the original story. Instead, he'd be more cautious and perhaps a bit more brooding, always thinking about the deeper meaning of things and the consequences of actions.
His personality would be greatly influenced by the forest environment. He would be more wild and free - spirited. Growing up away from the constraints of wizarding society, he would have a different set of values. He would be more empathetic towards animals and nature, seeing them as equals rather than something to be used. He would also be more solitary at first, but once he meets others, he would form very deep and loyal relationships as he values connection on a deeper level.