He'd probably be more confident. Dante is a very confident character, and if Harry is his son, he might inherit that trait. He'd be less likely to be intimidated by bullies like Draco or even the Death Eaters.
His view of good and evil might change. Growing up as the son of Dante Sparda, he'd be exposed to the idea that there are different levels of evil and different ways to fight it. In the wizarding world, the divide between good and evil seems more straightforward. But with his new heritage, he'd understand that there are gray areas. This could make him more empathetic towards some of the characters who are on the 'wrong' side, like some of the Slytherins who might be pressured by their families to side with Voldemort.
Well, it could involve Harry having some of Dante's devil - slaying abilities. Maybe he uses them to fight the dark forces in the wizarding world that Voldemort represents in a more unique way than just magic. For example, he could have enhanced speed and strength like Dante to take on Death Eaters.
His character would become more complex. He'd be more confident in his abilities, not just relying on his magic but also on his Sparda - given powers. He might be a bit more of a loner, as he tries to understand his unique identity. Harry would also be more fearless, knowing he has the strength of Sparda in him. This could lead to him taking more risks in his battles against the dark arts.
Harry would probably become more physically bold. Since Hercules was known for his strength and heroic deeds, Harry could be more likely to take on challenges head - on, using his physical abilities more often. His personality might also change in terms of his leadership. With the added boost of being related to a great hero, he could be more assertive in leading his friends and the Order of the Phoenix. He'd no longer be just the Boy Who Lived, but also the son of a powerful demigod, which would surely impact how he views himself and his role in the wizarding world.
He'd probably be more morally ambiguous. Growing up as Crowley's son, he might not have the same clear - cut sense of right and wrong as the original Harry. He could be more cunning and less hesitant to use underhanded tactics if necessary.
Harry would likely have a different set of values. Yugi had a strong sense of justice and friendship in Yu - Gi - Oh. As Yugi's son, Harry would place even more emphasis on these values. He might be more open to different cultures and beings, since the Yu - Gi - Oh world has a wide variety of characters. Also, his appearance might be a bit different, perhaps having some features that are more in line with the Japanese - inspired look of the Yu - Gi - Oh characters.
Harry's character could change in that he becomes more of a leader. With the special abilities and heritage from Hecate, he may find himself in situations where he has to take charge. He might also develop a deeper sense of responsibility, not just for his friends but for the wizarding world as a whole. He realizes he has a different role to play now that he is the son of a goddess. Also, he could become more attuned to the more mysterious and darker aspects of magic, which might make him seem a bit more brooding at times.
He becomes more conflicted. Knowing he's Voldemort's son, he's constantly in turmoil about his true nature. His confidence might waver as he wonders if he's capable of the same evil as his father.
He'd be more fearless. Sparda's influence would make Harry less afraid of danger. In the original, Harry was often scared but pushed through. With Sparda, he'd be more confident from the start.
It could make him more confident. With the symbiote's powers, he'd feel more capable in dangerous situations.
He'd probably be more confident. Knowing he's the son of Uther Pendragon would give him a sense of noble lineage. He might be more assertive in his actions and decisions, and less likely to tolerate injustice.