Well, in such a fanfiction, Harry would likely be exposed to the Malfoy's wealth and status from a young age. Narcissa could use her influence to keep Harry away from Dumbledore's manipulations (as some might see it in the original story). Harry might also learn more about the Dark Arts in a more controlled environment, as the Malfoys have some knowledge of it. However, he would still have his Gryffindor - like courage within him, which could create an interesting internal conflict.
One possible plot could be that Harry grows up with a different perspective on the wizarding world. Narcissa might shield him from the more extreme pure - blood ideologies in her own family. He could still have his natural talent for magic but be trained in a more Slytherin - like way, focusing on cunning and self - preservation. And he might have a different relationship with Draco, perhaps more of a brotherly bond.
If Narcissa adopts Harry, the story could change drastically. First of all, Harry's living situation would be completely different. He'd be in a luxurious Malfoy Manor. Narcissa would probably try to raise him as a proper pure - blood wizard. This could mean he has a different group of friends, perhaps more Slytherin - dominated. His relationship with the Weasleys might be strained. Also, his view of Voldemort could be more nuanced as he'd be hearing different things from the Malfoys. Harry would have to navigate his own identity, being both the Boy Who Lived and a Malfoy - adopted child, which would lead to a complex and fascinating story.
His personality might become more reserved. Growing up in the Malfoy household, he'd be surrounded by Slytherin values. So he could be more calculating and less impulsive compared to his original self. But he would still have that core of kindness from his parents.
In such a fanfiction scenario, Harry might be exposed to a very different upbringing. Lucius could try to indoctrinate Harry with pure - blood supremacist ideas at first. But as time goes on, Harry's strong sense of justice might conflict with Lucius's beliefs. Maybe Harry would gradually change Lucius's view on Muggle - borns, or he could use his influence within the Malfoy family to bring about some positive changes in the wizarding world's view on blood purity.
One possible plot twist could be that Malfoy's family initially objects to the adoption but then slowly comes to accept Harry. For example, Lucius Malfoy might see potential benefits in having Harry Potter, the famous wizard, in their family. Another twist could be that Harry, while growing up with the Malfoys, starts to influence them to be less prejudiced. He might introduce them to his friends from Hogwarts like Ron and Hermione, which would be a huge culture shock for the Malfoy family.
One possible plot could be a story where the wizarding world is in a state of great upheaval after the war. Harry, in his quest to bring about true peace and unity, finds himself working closely with Narcissa. Over time, they develop a deep understanding and respect for each other. Narcissa, having lost so much in the war, is drawn to Harry's sense of justice and kindness. Harry, on the other hand, sees Narcissa as more than just a Death Eater's wife. Their relationship blossoms in secrecy at first, as they both know it will be a shock to the wizarding community. Eventually, they decide to marry, much to the dismay and confusion of many, but also as a symbol of a new beginning that transcends old grudges.
In some fanfics, a plot twist could be that Narcissa was actually a spy for Dumbledore all along, and she was the one feeding him information about the Death Eaters. This completely changes the dynamics between her and Harry as they are on the same side without Harry even knowing.
Perhaps in the fanfic, Narcissa adopts Harry because she has a change of heart after seeing the destruction Voldemort causes. She wants to protect Harry as a way to atone for her family's association with the Dark Lord. Harry would then grow up in a Slytherin - influenced environment but still hold onto his Gryffindor values. This would lead to interesting interactions with other Slytherins and a different dynamic within Hogwarts.
One common theme is redemption. Narcissa was a Death Eater's wife, and in many fanfictions, she tries to redeem herself through her interactions with Harry. Another theme is the blurring of the lines between good and evil. Since Harry represents good and Narcissa was on the 'bad' side originally, their relationship in fanfics often challenges the traditional view of good and evil.
One unique fanfiction I remember is set in an alternate universe where Narcissa is a spy for the Order of the Phoenix from the very beginning. Harry stumbles upon her secret and they end up working together closely. The plot is full of twists and turns as they try to outwit Voldemort and his Death Eaters. It also delves deep into Narcissa's character, showing her as a strong and complex woman with her own motives and desires. In this story, their relationship is a key factor in the fight against the Dark forces.
One idea could be that Harry discovers Narcissa has a secret mission to undermine Voldemort from within. Maybe she's been secretly helping the Order of the Phoenix all along and Harry stumbles upon this knowledge.
There are many fanfictions on this topic. Some might explore how Narcissa's pregnancy would change her relationship with the Malfoy family and their stance in the wizarding world. It could also show how she might deal with the impending birth during the chaotic times in the story.