He might become more laid - back. Since he's constantly dealing with these dark creatures in a humorous way, he doesn't take things as seriously. For example, instead of being scared of a werewolf, he might just joke about its hairy appearance.
Harry's character in this fanfiction could transform in several ways. Firstly, he may become more adaptable. Having to deal with different dark creatures all the time means he has to quickly figure out how to handle each situation. This could make him more resourceful as well. He may also grow to be more empathetic towards these creatures. Instead of just seeing them as threats, he begins to understand their motives in a comical sense. For example, if a group of doxies are attracted to him, he might realize that they are just attracted to his shiny wand, thinking it's some kind of new shiny object to play with. So he starts to treat them more like naughty children rather than pests. This new perspective changes his overall attitude towards the magical world and its creatures.
In this fanfiction, Harry could become more confident. Dealing with the dark creatures that are attracted to him gives him a new sense of self - assurance. He realizes that he has a unique 'pull' on them, and he uses this to his advantage. He might start using his interactions with the creatures to gain knowledge or resources. For instance, if a group of imps are attracted to him, he might negotiate with them to get some rare magical items they've stolen. His character also might develop a more mischievous side. He starts to play pranks on the dark creatures, like tricking a boggart into changing into a really embarrassing form for itself.
Well, perhaps a thestral. Since Harry can see them, in this fanfiction they might be attracted to him in a rather odd way. They could fly around him in formation like a circus act whenever he's outside. And then there's the dementors. But instead of being all gloomy and soul - sucking, they might be attracted to Harry because he has some kind of 'bright' aura that they find really confusing and they just keep hovering around him trying to figure it out.
She becomes more confident. In these fanfictions, as fem Harry takes on the Dark Lady role, she no longer doubts herself like she used to. For example, in many stories, she used to be shy about using her magic, but as the Dark Lady, she wields it with great confidence.
It changes his character development in that he becomes more distrustful. Since he has the Dark Mark, he might start to doubt the intentions of those around him. He might think that people will always suspect him, so he becomes more withdrawn. Also, his sense of self - identity is shaken. He's no longer just the Boy Who Lived, but now he's someone with a mark associated with the darkest of magic. This could lead to him exploring his own morality more deeply. He might question if he's doomed to be like Voldemort just because of this mark, and he has to fight against that internal struggle to define who he really is.
Some dark creatures could have magical powers that are not fully understood. They could create barriers or illusions to hide Harry from his pursuers. In the fanfiction, they may also use their knowledge of the dark arts in a positive way to counter the dark magic aimed at Harry. They might be able to sense danger before it arrives and take preemptive action to keep Harry safe.
It changes him by making him more morally ambiguous. Instead of being the pure - hearted hero we know, he has a darker side. He might be more secretive and withdrawn as he delves into his newfound interest in the Dark Lord.
Fem Harry's character in these fanfictions can contribute to the humor by being more in touch with her feelings and expressing them in exaggerated ways. She might get overly excited about a new spell or get really angry at a mean professor in a very over - the - top way that makes the story funny. Her fashion choices in the fanfictions could also be a source of humor. Maybe she tries to combine muggle and wizarding fashion in the most outlandish combinations that leave everyone around her either shocked or laughing.
The fanfiction makes Harry a much more complex character. He's no longer just the good - hearted boy we know. As the new Dark Lord, he might have internal struggles. Maybe part of him still remembers his old values, but the dark power within him is overpowering those. This makes him a more morally ambiguous character, rather than the straightforward hero we're used to. For instance, he could be conflicted when it comes to harming his old friends, but still be driven by the new - found dark desires.
Perhaps vampires. Vampires are often powerful and if they have a reason to protect Harry, they could be very effective. Maybe they have a past connection with Harry's family or they see a future benefit in keeping him alive. There could also be creatures like basilisks. If they are tamed or controlled in the fanfiction, their deadly stare could be used against Harry's enemies instead of against him.
His character might become more hardened. In the world of Attack on Titan, he has to face the constant threat of Titans. So, he may lose some of his innocence and become more battle - ready, like the characters in Attack on Titan.
He often becomes more confident. With a harem around him, he has to step up and be more assertive in his relationships. He might also become more empathetic as he gets to know the different personalities in his harem.