A fanfiction could focus on Ichigo attending the school in Highschool DxD. His presence would surely disrupt the normal balance. He might not be interested in the whole 'devil' and 'angel' thing at first, but gradually get involved. He could also introduce some of his Soul Reaper training methods to the students there, which would be very different from what they're used to.
First, you need to understand the characters well. For Ichigo, know his personality traits like his determination and his sense of justice. For the Highschool DxD characters, understand their hierarchies and their goals. Then, come up with a unique plot. It could be a battle - oriented story where Ichigo and the DxD characters fight a powerful enemy together. Or it could be a more slice - of - life story where Ichigo adapts to the strange new world of DxD.
It could be a rogue Soul Reaper. Maybe someone who has turned against the Soul Society and sees Ichigo as a threat or a valuable asset. They might want to use his power to gain control over the Hollows or to overthrow the existing power structure in the Soul Society.
There could be a love story where Ichigo has a time - travel adventure and meets a version of Orihime from the past. This Orihime is different in some ways, yet still has the same kind heart. Ichigo has to keep his identity a secret at first, but as they interact more, he can't help but be drawn to her. She also feels a strange connection to this mysterious boy. As Ichigo tries to find his way back to his own time, he realizes that he has fallen in love with this different - yet - the - same Orihime, and the story becomes a race against time and his own heart.
Well, Ichigo could have a love story with Rukia. They have a very deep bond. Rukia is the one who first introduced Ichigo to the world of Soul Reapers. Their relationship is complex. There are moments of intense connection and understanding between them. They've fought side by side many times, and through these shared experiences, a form of love could develop. It might not be the typical romantic love at first, but it could grow into a deep and abiding love over time.
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.
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.
There could also be a powerful vampire hunter. This person might have a personal vendetta against vampires in general or specifically against Ichigo. They could use all kinds of weapons and tactics to try and kill him.
Well, a cool crossover fanfiction could be with the DC universe. Imagine Ichigo meeting Superman. They would surely have different views on justice. Superman is all about truth, justice, and the American way, while Ichigo is more about protecting his friends and the spirit world. Their meeting could lead to some intense debates and also team - ups against powerful villains.
It's hard to say. Ichigo has his Soul Reaper powers which are incredibly strong. He can cut through almost anything with his Zanpakuto. But Izuku has One For All which gives him superhuman strength, speed, and the ability to jump really high. So it depends on the situation.