Perhaps she is a seeker of some sort of ancient artifact that has significance in both the Bleach and Harry Potter lore. This could lead her to interact with different houses at Hogwarts, each with their own motives regarding the artifact. Some might want to use it for power, while others want to keep it safe. Her journey would involve not only finding the artifact but also dealing with the politics and rivalries within the wizarding school.
First, you need to understand the basic elements of both universes. Know the rules of the 'Bleach' world regarding Soul Reapers and Hollows, and also the magic system in Harry Potter. Then, think of a unique concept for your story. For example, what if Ichigo was a wizard in Hogwarts? Next, focus on character development. How would Ichigo and Rukia interact with the Potter characters? Finally, just start writing and let your creativity flow. Don't worry too much about making it perfect at first.
She could be a very brave character, like both Ichigo and Rukia. In the Harry Potter world, she would be fearless in the face of danger, just like when facing Hollows in the Bleach universe. For example, she might be the first to volunteer for dangerous tasks in Hogwarts, such as exploring the Forbidden Forest when strange things start to happen there.
One great Ichigo Rukia Harry Potter fanfiction is 'The Crossover Chronicles'. It combines the unique powers and personalities of Ichigo and Rukia from 'Bleach' with the magical world of Harry Potter in a really engaging way. The author does a wonderful job of creating new adventures for the characters in Hogwarts, while still maintaining their original essence.
In many fanfictions, their relationship starts from a place of mutual respect due to their fighting side by side. For example, in some works, as they face stronger enemies together, they begin to understand each other's motives better, which deepens their bond.
A really interesting plot development could be the connection between Loki's magic and the magic of the wizarding world. Harry could start to experiment with combining the two types of magic. For example, she might use Loki's magic of deception to create false horcruxes to mislead Voldemort. This could lead to a complex web of intrigue as Voldemort tries to figure out which are the real horcruxes and which are the fakes. At the same time, Harry could be exploring her relationship with her father through memories or encounters with Loki's essence, which would add a whole new emotional and character - driven aspect to the story.
A great fanfiction idea within this concept could be Ichigo and Rukia being mistaken for new types of magical creatures at Hogwarts. Their presence then disrupts the normal order of things at the school, leading to a series of adventures where they have to prove themselves while also dealing with their growing feelings for each other and the new friends they make in the Harry Potter world.
It might develop through a series of battles and near - death experiences. For instance, if they are in a fight against a common foe and Hollow Ichigo saves Rukia's life. This act could make Rukia reevaluate her view of him. Similarly, if Rukia shows kindness or understanding towards Hollow Ichigo in a moment when he least expects it, it could thaw his cold exterior towards her, gradually building their relationship.
Ichigo might develop more patience in a school setting. Since he's often hot - headed, being in school with all its rules and social interactions could force him to rein in his temper. For example, when dealing with a strict teacher or a bully. Rukia, on the other hand, could become more open. School is a place full of different personalities, and she might be exposed to more friendly and outgoing students, which could make her less reserved over time.
In a fanfiction where Fem Harry is Voldemort's daughter, it could lead to a whole new set of adventures. She might struggle with her identity, not knowing whether to embrace her father's dark side or follow the path of good. Her magical abilities could be a mix of Voldemort's dark magic and something more. For instance, she might have an easier time with dark spells but also possess a hidden power for good. The Death Eaters could have a different attitude towards her. Some might try to recruit her, while others might fear her as a potential threat to Voldemort's rule. This would create a lot of internal conflict for Fem Harry, as she tries to figure out where she belongs in this strange new world.
Some fanfictions develop their relationship by showing their everyday lives in a more detailed way. We see them interact during their downtime, like when they are just chatting over a meal or walking around Karakura Town. These small, normal moments can add a lot of depth to their relationship as we see different sides of their personalities.