Ichigo would probably be devastated. His trust in relationships would be severely shaken. He might become more withdrawn and focus even more on his battles and training, using it as an escape from the pain of the betrayal. He could also become more cynical about love and people in general.
Perhaps in the fanfic, Ichigo has changed a lot over time. He might have become too focused on his power and his battles. His partner could feel left out and alone. There could be someone else in their life who offers them the attention and affection they crave. In this case, they might cheat on Ichigo. Fanfic writers often like to take characters out of their comfort zones and explore how they react to difficult situations like this.
Another way Ichigo could get his powers back in fanfiction is through a magical or spiritual artifact. Maybe he discovers an ancient sword or a talisman that has the ability to restore his lost powers. This could be part of a grander plot where he has to go on a quest to find this item, facing various challenges and enemies along the way. During this journey, he might also learn more about the true nature of his powers and how they are connected to the overall 'Bleach' universe.
One possible plot twist could be that Ichigo, now as a girl, has to deal with different power dynamics. Maybe her reiatsu (spiritual pressure) is affected in a new way. For example, it could become more refined or have a different color, which would attract different kinds of Hollows or Soul Reapers. Another twist could be in her relationships. Her friends might initially be shocked and not know how to interact with her. Uryu, for instance, might be more hesitant to be around her at first. Also, the Soul Society's reaction could be interesting. They might be suspicious of this change and think it's some kind of new threat or a trick by the Quincy. Overall, the story could explore how Ichigo's personality remains the same despite the physical change, but she has to adapt to the new social and power - related situations.
It could be a fanfiction that delves into the power dynamics. Since Ichigo has three zanpakuto, perhaps it shows how his power has increased exponentially. It might also be about the training he had to go through to be able to handle three zanpakuto, and how this changes his role in the Bleach universe.
One idea could be that the female Zanpakuto has a unique personality. For example, she could be sassy and constantly tease Ichigo while also being fiercely protective of him. In the fanfiction, she might have her own backstory, like being created from an ancient power that was sealed away for centuries until Ichigo awakened her.
It could completely change the dynamics of his powers and battles. Maybe a new Zanpakuto would give him unique abilities or force him to adapt his fighting style in unexpected ways.
Well, her Zanpakuto's abilities might change. Zangetsu could have new powers that are more in tune with a female form. For example, it could have powers related to healing or protection in addition to its normal combat abilities. Her physical strength might be replaced with a more strategic and cunning approach to battles. She could use her surroundings and the enemy's weaknesses more effectively. And her connection to the Hollow inside her could also be different. It might be more of a partnership rather than a constant struggle for control, and this could lead to new combined forms with different power sets.
In some fanfictions, there could be new characters introduced specifically for this arc of Ichigo getting his powers back. For example, an old and powerful soul reaper who has some special knowledge or ability related to Ichigo's powers. They could play a crucial role in guiding Ichigo, training him, or even sacrificing themselves to help him regain his powers. Additionally, villains would also be main characters in a sense. They could be the ones who initially took Ichigo's powers or are trying to prevent him from getting them back, thus creating the conflict in the story.