One possibility could be that Ichigo is under some sort of mind - control. Maybe an enemy has found a way to manipulate his actions and he ends up hurting Rukia without meaning to. This could lead to a lot of internal conflict for Ichigo once he realizes what he has done.
Perhaps there is a misunderstanding between them. Ichigo might think Rukia has done something that goes against his principles, like siding with an enemy he believes is truly evil. In his anger, he lashes out at her, but later discovers that he was wrong.
It could also be a situation where Ichigo is forced to choose between saving Rukia or a large number of other people. In his difficult decision - making process, his actions end up causing harm to Rukia. This would create a very complex and emotional story arc.
If it was a serious enough injury, Rukia might even start to resent Ichigo. Their relationship could change from a close friendship to one filled with animosity and mistrust. However, if Ichigo shows true remorse and tries to make amends, there could be a slow rebuilding of their relationship over time.
There's 'Soulmate's Journey' which is a really popular one. It delves into the idea that they are soulmates in a more spiritual and emotional sense. It has some really touching moments that show their love and loyalty to each other. It also includes some great action scenes that are true to the Bleach universe.
One possible plot could be that Ichigo is kidnapped by a powerful and unknown enemy. This enemy might be from a different realm or a secret organization within the Bleach universe. His friends then embark on a quest to find him. They might face various challenges and battles along the way as they try to track down Ichigo's location.
One possible plot could be that Ichigo and Rukia are paired for a school project. They start off not getting along very well because of their different personalities. Ichigo is impulsive and Rukia is more reserved. But as they work together, they gradually learn to understand and respect each other. They might face challenges like finding a suitable topic, dealing with difficult classmates who try to disrupt their work, and finally presenting their project successfully which also strengthens their friendship.
The potential for different storylines is a big factor. In the anime/manga, their relationship was left with some room for interpretation. Fanfiction writers can take this and create all kinds of scenarios, like alternate universes where they are from different social classes or have different powers. This allows for a lot of creativity and exploration of their characters.
One possible plot could be that Ichigo kidnaps Rukia out of a desperate need to protect her from some unseen and extremely dangerous threat in the Soul Society. He might believe that the Soul Society's own mechanisms for safeguarding her are insufficient.
Well, it could be about their baby having some sort of special power. Maybe the baby inherits both rukia's shinigami powers and ichigo's hybrid powers. It could grow up in a world where it has to learn to control these powers while also facing the challenges of being the child of two very important and powerful beings.
Well, it could be about Ichigo teaching Izuku some combat skills. Since Ichigo is a powerful Soul Reaper, he might show Izuku how to better use his physical strength and speed in battle.
One possible plot could be a post - battle scenario. After all the chaos and fighting they've been through, Ichigo realizes his true feelings for Rukia. They start to secretly date while trying to maintain their duties as Soul Reapers and protectors of the living world. Eventually, their friends find out and support them wholeheartedly. They plan a simple yet beautiful wedding in the Soul Society, with all their friends and comrades in attendance, and they live happily ever after, constantly going between the Soul Society and the living world to visit their loved ones.
Well, it could be about their adventures together after the main events in Bleach. Maybe they go on a mission to a new realm and face new enemies while strengthening their bond as friends and comrades.