Perhaps in the 'ichigo travels back in time bleach fanfiction', Ichigo travels back to the time when the Soul Society was in a more fragile state. He could use his knowledge from the future to help strengthen the Soul Society against upcoming threats, like Aizen's plans. He might train the younger versions of the Soul Reapers and form new alliances that would change the future battles.
Aizen could still be the main antagonist. Even if Ichigo travels back in time, Aizen's long - term plans might be already in motion. Ichigo would have to find a way to expose and stop Aizen earlier than in the original timeline.
One possible plot could be that Esme travels back to a time when she was about to make a crucial life decision. For example, she might go back to the moment before she met her significant other. In the past, she could then have the chance to see things from a different perspective. Maybe she realizes that the decision she made back then was actually the best one, or she might find out new things about herself or the people around her that she didn't know before, which could lead to a whole new set of adventures and self - discovery in the past and ultimately change her view of her present life.
One possible plot could be that after all the battles in Bleach, Ichigo discovers a new side of Rangiku and they fall in love. They get married secretly to avoid the chaos it might cause in the Soul Society and the human world. Then they have to face the challenges of hiding their relationship from their friends and families while also dealing with new threats that target them because of their union.
The story could then develop as Ichigo tries to find a way back home. Along the way, he gets caught up in the politics and battles of the DxD world. He might meet Issei and initially be at odds with him because of their different outlooks on power and combat. But as they face common enemies, they start to work together. Ichigo could also have run - ins with powerful devils like Sirzechs Lucifer, who might be intrigued by his power and want to either recruit him or eliminate him as a potential threat.
One possible plot could be that Ichigo is hit by a strange Hollow attack that not only changes his physical form to a girl but also gives him new powers. He then has to adapt to this new body while still facing the usual threats in the Bleach universe. His friends might initially be shocked but quickly accept him and help him figure out how to reverse the transformation while still using his new - girl - form - related powers to fight enemies.
Well, a really interesting plot twist in an Eren travels back in time fanfiction could be related to relationships. Say Eren goes back and realizes that his actions in the past have a huge impact on his relationships with his friends. Maybe he accidentally causes Mikasa to not be as attached to him as she was in the original timeline. Or he could find out that Armin was supposed to be the one with the time - traveling ability all along, and his interference messes up Armin's future plans. Also, what if he goes back and discovers that the real enemy wasn't the Titans but some other force that was using the Titans as a distraction, and his time - traveling journey is the only way to expose this truth.
A plot twist could be that Sakura travels back in time and realizes that the world she thought she knew was all a lie. The history books in her time were wrong. She could find that the origin of her magical powers was something very different from what she was taught. Also, she might go back to a time when there was a powerful artifact that was lost in her own time. However, when she tries to retrieve it, she discovers that it has a dark side that she didn't expect. This could lead to a moral dilemma for her, whether to keep it or leave it be.
One possible plot could be Ianto Jones going back in time to prevent a major disaster in Torchwood's history. Maybe he travels back to the time before the Cardiff Rift opened in such a large and dangerous way. He could use his knowledge from the future to stop an alien invasion that was the root cause of the rift's instability.
One possible plot could be Korra going back in time to prevent a great disaster that she has knowledge of in her own time. For example, she might go back to stop the start of a war that had long - lasting negative impacts on the world. She could use her bending skills in new and unexpected ways in the past, as the technology and bending styles of that time might be different.
The plot could involve a power - sharing concept. Hollowfied Ichigo, with his unique power, might accidentally transfer some of his Hollow energy to Tier Harribel. This new - found power could either be a boon or a curse for her. She may struggle to control it at first, and Ichigo would feel responsible for helping her. This could lead to a journey of self - discovery for both of them as they learn more about each other's powers and themselves.