His sense of self - preservation might be extremely high. The monster's world is likely a more dangerous one compared to a typical wizarding family. So, Harry would have learned from a young age to look out for himself first, which could make him seem a bit more self - centered at times, but also very resourceful when in danger.
He might be more feral. Growing up with a monster, he could lack some of the social graces that a normal upbringing in the wizarding world would provide. He may be more direct and less concerned with propriety.
He might be more laid - back. Canadian culture is often seen as more relaxed, so Harry could have a calmer demeanor. He wouldn't be as quick to get into arguments or be as impulsive as he sometimes was in the original story.
Harry might be more confident in his pure - blood heritage. Since Dorea Black would likely educate him about it, he wouldn't feel as out of place among the pure - blood families as he did in the original story. He may carry himself with more pride, but not in an arrogant way.
He'd probably be more sophisticated. The Delacour family is known for their elegance and grace. Harry might have a more refined way of speaking and acting compared to his canon self. For instance, he would be more likely to use formal French wizarding greetings.
His personality would likely be more reserved and calculating. Growing up with the Malfoys, he'd be taught to keep his emotions in check and think before acting. He might be more aloof towards others outside of the pure - blood circle at first.
His sense of humor would likely be different. Sirius has a bit of a mischievous streak, and Harry would pick up on that. He might be more prone to making jokes and playing pranks in a more light - hearted way compared to the somewhat more reserved Harry we know from the original story. Also, Harry would be more trusting of others in general, especially those in the wizarding world, as Sirius would introduce him to a more positive side of it from the start.
Percy's personality would be more in tune with nature. Since Artemis has a strong connection to nature, Percy would grow up respecting and understanding it more deeply. He would probably be more solitary as well, as the hunters often keep to themselves. He might not be as quick to trust others as he used to be, having been brought up in a more exclusive group. Also, he would have a greater sense of loyalty towards Artemis and the hunt, which could make him seem a bit cold to outsiders.
Percy could be more in tune with his emotions. Dionysus is associated with passion and ecstasy, so Percy might be more openly emotional, not suppressing his feelings as much as he did in the original stories. He could also be more creative, as Dionysus has an element of creativity in his domain. For example, he might be better at coming up with unique solutions to problems using his more artistic side.
He'd likely be more withdrawn and edgy. Constant exposure to the creepy elements would make him less trusting and more on - guard all the time.
He'd probably be more refined. The Delacours are known for their elegance, so Harry might have better manners and a more sophisticated way of speaking.
If Harry was raised by his grandparents in fanfiction, his personality would change in several ways. For starters, he would be more self - assured because he'd grow up in a loving environment. He wouldn't have the same insecurities that came from being treated as an outcast at the Dursleys. He'd be more extroverted, as he wouldn't be afraid to show his true self. His sense of humor might be different too, perhaps more light - hearted and less sarcastic as a defense mechanism. He'd also have a stronger sense of family and heritage, which would influence his actions and decisions.