Obviously, Ichigo is the central character in 'ichigo goes beyond bankai fanfiction'. But we can't forget about his mentor figures like Urahara. Urahara has always been a bit of a mystery and has a lot of knowledge about spiritual powers. He could be crucial in helping Ichigo understand and master his new powers. Then there are Ichigo's opponents. There might be new and powerful adversaries who are either threatened by Ichigo's new power or are trying to harness it for themselves. These opponents would also be important characters in the story.
One interesting plot point could be Ichigo's new powers and how they change his battles. For example, he might have abilities that allow him to manipulate time or space in combat. Another could be the reactions of his friends and foes to this new level of power. His friends might be in awe or a bit worried about his newfound strength, while his enemies would likely be more fearful and have to come up with new strategies to face him.
It could be a young hero named Alex. Alex might be brave and curious, always eager to explore the unknown areas beyond the darkness.
The main characters are Abraxas and Ichigo. Abraxas often has some sort of magical or special abilities that set the story in motion. Ichigo, on the other hand, usually has his own set of skills or powers that complement Abraxas's.
Uryu could also be a main character. He might be initially skeptical of Ichigo's transformation into a dragon god but then come to respect and even rely on his new powers in battles against common enemies. His Quincy abilities could contrast with Ichigo's dragon god powers, creating interesting interactions between them.
One potential ally could be a friendly youkai student who is intrigued by Ichigo's godlike powers. Maybe someone who is an outcast among the youkai and sees Ichigo as a kindred spirit.
There could be some of the more benevolent yokai who see Ichigo as a potential ally. For example, the werewolf Koga might recognize Ichigo's strength and see an opportunity to team up with him against common enemies. Maybe even some of the teachers at the academy who are tired of the chaos and power plays could join forces with Ichigo.
There could be some new characters who are splicers themselves. Maybe a lead splicer character who is trying to create a new world order for the splicers. This character could be complex, having both good intentions for his splicer kind but going about it in the wrong way, like causing chaos in Gotham.
Terry McGinnis is bound to be a main character. He is Batman in this future setting. His alter - ego as a young man trying to balance his normal life and his duties as Batman would be central to the story.
In addition to the main RWBY girls, there could be new characters introduced in 'beyond the boundary rwby fanfiction'. These new characters might be from the areas beyond the boundary and could have their own unique abilities and backstories.
There could also be a mix of both. Some of the main characters could be well - known from the original work, and others could be original creations. For example, in a fanfic based on a popular book series, the main protagonist from the book might form a bond with a new character created by the fanfic author. This new character could bring in a new perspective on time and how bonds can exist beyond it, and together they make up the central focus of the story.