It makes him more cautious. Since he knows the law, he's aware of the consequences of his actions more than ever. So he might think twice before using certain spells or getting involved in risky situations.
Harry's knowledge of the law in the fanfiction can transform his character into a more strategic thinker. He has to analyze situations from a legal perspective, which means looking at all the possible outcomes and implications. This forces him to be more patient and less impulsive. Instead of just reacting to threats, he can plan ahead and use the law to his advantage. For instance, when dealing with school bullies or even more dangerous foes, he can find legal ways to neutralize them, which is a big shift from his more straightforward, action - based approach in the original series.
He might use it for protection. For example, if someone tries to harm him or his friends, he uses laws about magical self - defense to stop them.
In the original story, Harry's main concern was the fight against the dark forces. But in a fem Harry Potter marriage law fanfiction, her priorities are somewhat redirected. The law might require her to marry into a certain family to gain political or magical advantages. This could mean she has to make deals and compromises she wouldn't have in the original story. Also, her relationships with other characters like Hermione and Ron would be redefined. Hermione might be more involved in helping fem Harry understand and deal with the marriage law, and Ron might have different feelings if he sees fem Harry being forced to consider other potential partners. All in all, it significantly alters the character dynamics and the overall flow of the story.
His character may become more confident. Knowing his heritage gives him a sense of identity, so he might stand taller and be more assertive in the wizarding world.
In Harry Potter fanfiction, the application of marriage law can vary greatly. Some fanfics might follow the wizarding world's own traditional 'rules' of marriage which could be different from Muggle marriage law. For example, there could be magical contracts involved in wizarding marriages that are not present in the Muggle world.
He might become more in tune with nature. Since the Phoenix is a symbol of rebirth and nature in the wizarding world, Harry could develop a stronger sense of environmental magic. For example, he could be able to communicate with other magical creatures more easily, not just the Phoenix.
He becomes more humble. Elves are used to serving and being in a subservient position. Growing up with them, Harry would learn the value of every being, no matter their status. He'd be less likely to show off his magical abilities like he might have in the original story.
He becomes more brooding. The knowledge of necromancy and the power it brings can isolate him as he realizes it's a power not many understand or accept. So he might withdraw from his usual jovial self.
He might become more sneaky and calculating. Since he's a thief now, he would have to be good at hiding his actions and planning his 'heists'. His moral compass might also shift a bit as stealing isn't exactly an ethical behavior in the normal wizarding world.
Well, one interesting aspect could be how Harry uses his knowledge of magic law to solve mysteries within Hogwarts. Maybe he discovers some loophole in the school rules that helps him and his friends out of a tricky situation.
In 'Harry Potter son of Loki' fanfiction, Harry changes significantly. His sense of identity is greatly shaken. He no longer just sees himself as a simple wizard. He now has this connection to Norse mythology. This makes him more curious about different forms of magic and otherworldly things. He may become more of an outcast as well, since his heritage is so different. But this also makes him stronger in some ways. He has to rely on himself more and develop his own unique set of skills and powers that come from both his Potter and Loki lineage.