His magic might be more aggressive. Growing up with the Dark Lord, he would be taught to use magic for more forceful and often cruel means. For instance, instead of using a simple Stunning Spell like in the original, he could be using more dangerous and unforgivable - like spells without hesitation.
His magic could be more combat - oriented. Jiraiya's ninja background would likely influence Harry to use magic in a more direct and aggressive way in battles, rather than just for defensive or utility purposes like in the original series.
Harry's magic could be stronger. Dorea's influence and knowledge of magic could have allowed Harry to tap into his magic potential more easily. Maybe he would be able to perform advanced spells earlier. Also, his magic might have a different 'flavor' so to speak. Since Dorea comes from a different magical background than the Dursleys, Harry's magic could be more attuned to the traditional wizarding ways of magic use.
Well, in this fanfiction scenario, Fem Harry Potter's magic would be distinctively different. Since Poison Ivy has a strong connection with plants, Harry would be taught to harness the power of plants for her magic. She may not rely as much on incantations as in the original story. Instead, she could simply touch a plant and transfer her magic into it to make it do her bidding. Her magic would be less about structured spells from books and more about the instinctive connection with nature. For instance, she could make a flower bloom instantly and use the pollen to blind an opponent or create a path of growing plants to reach a high place instead of using a levitation spell.
He would be more refined. Royal upbringing would instill in him a sense of propriety and elegance that he lacks in the original story.
His magic might be more elemental. Since Greek magic often ties in with the elements like fire, water, earth, and air. He could have an easier time with spells related to these elements compared to other Hogwarts students.
Harry might have an easier time with spells related to transformation. Just as Poseidon can change the form of water, Harry could be more adept at transfiguration spells. He could also have a natural ability to breathe underwater and perform magic while submerged, which would be a huge advantage in certain situations. This would open up new possibilities for him in both the wizarding world and any underwater adventures he might have.
Harry would likely be more fearless and brash. Kenpachi is a bold and fearless fighter, and his influence would make Harry less hesitant. For example, when facing a bully like Draco, Harry might immediately react with physical force rather than just trading barbs. He would be more upfront and direct in his approach to problems.
His magic might develop in a more instinctive and self - taught way. Without the guidance of Hogwarts professors, Harry would have to figure out his magic on his own. He might use it more for survival and self - defense against the threats that Jason's world presents. For example, he could use magic to create barriers or traps to keep enemies at bay.
Harry's character could develop into a more serene and centered individual. Lady Magic's influence could instill in him a sense of calm and purpose. He would not be as easily rattled by the challenges that come his way. For example, he might face Voldemort with a different kind of confidence, not just the courage that comes from his friends and Hogwarts, but from his own deep - seated connection to the very source of magic. This could also make him more empathetic towards magical beings, as he would understand the magic within them on a deeper level.
Harry's relationship with Dumbledore could be one of the most interesting changes. Dumbledore would likely see Harry as a very different kind of wizard. He might be more cautious in guiding Harry, as he tries to understand the influence of Poison Ivy. Harry, on the other hand, might not be as quick to trust Dumbledore as he was in the original story. He could be more independent and question Dumbledore's motives more often, especially if he felt that Dumbledore's actions were not in line with the values he learned from Poison Ivy, which are more centered around nature and its protection.