In many fanfics, Fleur is often depicted as strong - willed. She's a Veela, so she has that alluring quality, but she's also smart and not just a pretty face. For example, in some fanfics she uses her Veela charm in a strategic way to get what she wants or to protect others.
Often, Luna Lovegood can be found in such fanfictions. Her unique and dreamy nature could bring a different dynamic to the harem. Neville Longbottom might also be involved in some way, perhaps as a friend who supports the harem and helps them out in times of need. There could also be some foreign exchange students or magical creatures in human form that end up in the harem for various reasons.
At first, their relationship might be a bit strained. Harry is used to his own space and friends, and Fleur has her own circle. But as they live together, they'll start to respect each other's differences. For example, Fleur might be more flamboyant in her magic use, while Harry is more practical. They'll start to see the value in each other's approaches and become closer friends.
Hermione would probably be a bit skeptical at first. She might worry that Harry is rushing into things. But once she sees how happy they are, she would be supportive. Ron, on the other hand, would be more accepting from the start, especially if there are good feasts at the wedding.
Often, Harry's sense of responsibility grows. He starts to see the marriage contract as not just a burden but also an opportunity to create a new life for himself and Fleur. Fleur's personality may develop in a way that she becomes more protective of Harry. For example, when they face opposition from the wizarding community about their contract, she stands up for them. She also might help Harry to overcome his insecurities about being in a relationship with someone as glamorous as her.
At first, they might be at odds with each other. Fleur could think Harry is too impulsive, while Harry might find Fleur a bit too haughty. But then, when they are forced to work together on a mission, they see the good in each other. Fleur realizes Harry's selfless nature, and Harry sees Fleur's intelligence and determination. This new - found respect leads to a romantic relationship and ultimately marriage.
In a Master of Death Harry Fanfic, Harry's character development would be complex. He would have to grapple with the enormity of his new power. At first, he might be tempted to use it for revenge against those who wronged him in the past. But as he matures, he realizes that his power should be used for the greater good. He would also become more solitary as he has a power that few can understand, but he would still cherish his true friends even more.
The relationship could start with mutual curiosity. Harry, as Lord Black, is a novelty in the wizarding world, and Fleur wants to know more about him. They might exchange letters at first, getting to know each other's thoughts and ideas.
They would probably have a close relationship. As siblings, they'd likely look out for each other. Fleur might be protective of Harry, and Harry would respect and admire his sister. Since Fleur is older and more experienced in the wizarding world in some ways, she could be like a mentor to Harry at times.