One consequence could be that his relationships change. His friends might not recognize the new 'soul - changed' Harry at first, leading to some initial confusion and distance in their friendships.
There could also be a change in his connection to the wizarding world's magical core. Since his soul is an integral part of his magical being, a change in it might mean that he has a different relationship with the magic that flows through the world. For example, he might be more in tune with certain aspects of magic, like nature magic, while losing some of his previous affinity for more traditional spells.
His magical abilities might be affected. If his soul is changed, the way he channels magic could be different. He might find that some spells that were easy before become difficult, or he might discover new, previously unknown magical powers that come with the changed soul.
In some fanfiction concepts, he might change his soul through powerful magic spells. Maybe he discovers an ancient spell in a hidden book in the Room of Requirement that has the power to transform his very essence, his soul.
There are indeed 'Harry Potter sold his soul' fanfictions out there. It's a very interesting, if somewhat disturbing, concept. In some of these fanfictions, the author might use it as a way to explore different aspects of the wizarding world that were not fully explored in the original books. For example, they could show how the dark magic associated with selling one's soul interacts with the existing magical laws and institutions in the wizarding world. It could also be a way to look at Harry's character from a completely different perspective, seeing how his personality might be altered by such a huge sacrifice and the subsequent influence of dark forces.
One common theme is the exploration of darkness. Since selling one's soul is a very dark act, fanfictions often focus on how Harry's world becomes filled with more sinister elements. Another theme could be the loss of self. Harry might struggle with losing his identity as he is influenced by the dark forces that now have a claim on his soul.
In some cases, he could become a puppet for the dark side. Without his soul, he has no moral compass, so he could be easily manipulated by the forces of evil to do their bidding. His friends would then be in a race against time to restore his soul before he causes too much harm.
One consequence could be an alteration in the relationships. For example, if he saves Sirius, the relationship dynamics between him, Remus, and the other members of the Order would be different. They might be more united and effective in fighting against the Death Eaters.
One consequence could be that Harry feels an internal struggle. Since he has a part of Voldemort's soul in him, he might have to constantly fight against the dark impulses that come with it. For example, he may find himself having more aggressive thoughts or being more easily influenced by dark magic in certain situations.
Maybe he was hit by a powerful dark magic spell specifically designed to target the soul. Such spells in the Harry Potter universe can be extremely dangerous.
If such fanfiction exists, it may lead to a lot of negative impacts. It can mislead some young and inexperienced readers into thinking that abnormal relationships are acceptable. Moreover, it might face legal issues in some cases as it violates ethical and moral boundaries. Also, it will be shunned by the vast majority of the legitimate Harry Potter fandom who uphold the positive values of the series.
One consequence could be a breakdown in their friendship. His friends might feel hurt and start to distance themselves from Harry. For example, Hermione, who is very loyal, might be deeply offended if Harry constantly doubts her.
In the realm of Harry Potter fanfiction, 'harmony the soul bond' is an interesting concept. It's likely a fictional creation within the fan - made stories. This type of bond can be seen as a way to explore different relationships between characters. It could be a way to show how two characters are meant to be together in a more profound sense. Maybe it's a bond that is discovered gradually throughout the story. For instance, the characters might start as friends and then realize they have this 'harmony the soul bond' as they go through various challenges together. It can add a new layer of depth and drama to the fanfiction, making the relationships between characters more complex and engaging.