Perhaps a plot twist would be that during the fight, Tai discovers a secret about Raven that completely changes his perception of her. For example, he finds out that she has been working undercover to stop a greater threat all along, and their fight then turns into a reluctant alliance against a common enemy.
In the 'rwby tai vs raven fanfic', it might focus on the backstories that led them to this point of conflict. Tai might be fighting for the sake of his family or his ideals about protecting Remnant. Raven, on the other hand, could be in the fight for her own self - interest or to protect secrets she holds. The fanfic could also show how their relationship, whether it was once friendly or always strained, affects the way they fight each other.
Tai might be amused or intrigued. He could have a positive reaction if the fanfiction shows the characters in a new and interesting light. Maybe he'd laugh at some of the creative interpretations. Raven, on the other hand, might be more critical. She might not like it if the fanfiction doesn't align with her view of the RWBY world or the characters. She could also be dismissive if she doesn't see the value in fan - made stories.
One possible plot twist could be that Adam has a hidden weakness that Sun discovers during the fight. Maybe it's related to his past or his weapon. Another could be that Sun is actually being controlled by an outside force and Adam has to decide whether to take advantage of it or help him.
One possible plot twist could be that Danzo is actually being controlled by an even greater enemy. So, when Naruto is about to defeat him, he realizes that there's a bigger threat behind Danzo. Another could be that Danzo reveals a hidden power that he has been suppressing all along and suddenly becomes much stronger than Naruto expected.
One possible plot twist could be that Naruto discovers Godzilla is being controlled by an evil force. So instead of just fighting Godzilla, he has to find a way to break the control. Another could be that Godzilla is actually a guardian of some sort, and Naruto misinterprets its actions as aggression at first. Then they end up teaming up against a greater threat.
One possible plot twist could be that Naruto discovers a way to nullify Jigen's power. Maybe he finds a weakness in the power source that Jigen draws from. Another twist could be that Jigen is actually being controlled by a greater evil, and Naruto has to figure out a way to free him rather than just defeat him. It could also be that Naruto loses his powers temporarily during the fight and has to rely on his wits and the help of his friends in unexpected ways.
One possible plot twist could be that the character who seems to be the betrayer is actually being framed. Another might be that the betrayal is part of a bigger plan to save the RWBY world from an even greater threat.
Perhaps the story could revolve around Raven's son trying to bring her back from the dark side. He might use his unique bond with her, as her son, to try and make her see the error of her ways. Along the way, he could team up with the main RWBY characters, facing various challenges and battles together. This would not only explore his relationship with Raven but also his place in the larger RWBY universe.
Well, perhaps the plot could revolve around Raven still being part of the main story in RWBY. Maybe she continues to be involved in the battles against the Grimm. She could also play a role in the relationships between the main characters like Ruby and Yang. For example, she might help train them or offer her unique perspective on the events that unfold in the RWBY universe.
A great plot twist could be that Raven is actually working undercover for a good cause all along, and Qrow discovers this in the middle of a fight against her. He thought she was a villain, but in reality, she was trying to stop a greater evil from within the enemy's ranks.