In a 'female Ichigo betrayed' fanfic, it could be that she betrays due to a misunderstanding. She might overhear or misinterpret something that makes her think her friends have betrayed her first. For example, she could think they were planning to sacrifice her for the greater good of the Soul Society. So, in her anger and hurt, she decides to side with their supposed enemies, only to later find out the truth and have to deal with the consequences of her actions.
Well, perhaps in the fanfic, female Ichigo betrays her allies because she has been brainwashed. Some sort of evil entity or powerful Quincy could have gotten into her head and made her believe that her friends are the real enemies. So she begins to pass on their secrets and even attacks them, leading to a lot of chaos and heartbreak among her former friends.
There could be Byakuya. He would be shocked and disappointed by female Ichigo's betrayal as he might have seen her as a promising comrade. Also, Rukia. Since she and Ichigo have a special bond, her reaction to Ichigo's betrayal would be very emotional. And then there's Aizen. He could be the one who tempted or manipulated female Ichigo into betraying, seeing her as a useful pawn in his grand schemes.
One possibility could be that Ichigo is betrayed by a close friend during his time - traveling adventures. Maybe this friend is jealous of Ichigo's powers or has been influenced by an enemy. This betrayal could lead Ichigo to question his relationships and his purpose in the time - traveling journey. He might then have to find a way to overcome this betrayal and still fulfill whatever mission he has in the different time periods.
One possibility could be that during his time travel, Ichigo discovers that his friends or allies in the future have turned against him for some reason. Maybe they believe he has become too powerful and is a threat. So they plot to betray him, which sets up a conflict where Ichigo has to fight against those he once considered friends while also trying to figure out a way to fix the timeline.
Well, sometimes in these fanfics, Ichigo is betrayed by his Hollow side. It could be that the Hollow part of him has its own agenda and decides to use Ichigo's friends as bait to draw out more powerful opponents. This would make Ichigo feel extremely guilty as he's the one who brought this danger to his friends. Also, there could be a plot twist where Ichigo is betrayed by a new character introduced in the fanfic. This new character might have pretended to be his ally all along but was actually working for a powerful antagonist. This would make Ichigo realize that he can't trust people so easily.
Well, it could be about Bulma being betrayed by a close friend in the Dragon Ball universe. Maybe that friend reveals her secrets to an enemy, like her latest inventions or the location of the Dragon Balls she was guarding. This would put her in a dangerous situation and lead to a series of adventures where she has to fix the mess.
In the fanfic, it could be that there is a mysterious force threatening the Soul Society. Ichigo and Unohana team up to investigate. Along the way, they discover secrets about each other's pasts. Unohana's past as a fearsome warrior is revealed to Ichigo, and Ichigo's insecurities and determination are exposed to Unohana. Their relationship evolves as they work towards defeating the threat.
The plot could be that Ichigo has a dream where she is in a chocolate wonderland. She wakes up and decides to explore more about chocolate in the real world. She starts going to chocolate tastings and meets a chocolatier who teaches her how to make chocolate sculptures. This could lead to her entering a chocolate - making competition.
In the '4 kunoichi gets betrayed fanfic', it could be that the four kunoichi are working for a noble cause. However, one of their own, due to jealousy of the attention the others get, decides to betray them. She spreads false rumors about them, making the whole ninja community turn against them. The four kunoichi have to prove their innocence and also figure out a way to deal with the traitor within their group.
It could also be a misunderstanding. Hinata might be under some sort of mind - control or false impression. For example, an illusion is cast on her that makes her believe Naruto has become evil. As a result, she takes actions against him that he perceives as betrayal. In this case, once the truth is discovered, they would likely reconcile.
It could be that Ash discovers some sort of secret about Harrison that he misinterprets. Instead of talking to Harrison about it, he takes actions that seem like a betrayal. For instance, Ash might tell others about this secret, thinking it's for the greater good, but it actually causes a lot of harm to Harrison.