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.
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 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.
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 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 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.
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.
One possible plot twist could be that Pikachu suddenly loses its ability to use electric attacks. This would completely change the dynamic of the battle as Pikachu would have to rely on physical attacks like Quick Attack, which might not be as effective against Bayleef. Another twist could be that Bayleef evolves during the battle into Meganium, gaining new and more powerful abilities that catch Pikachu off - guard.
One popular RWBY Raven and Tai fanfiction is 'The Unspoken Bond'. It delves into their past relationship and how it affects their current interactions within the RWBY universe. It has great character development and an engaging plot.
A great plot twist would be if Raven is kidnapped and taken to a place where she meets her long - lost family members, but they're the ones who kidnapped her because they need her help to fight against a common enemy, and they knew this was the only way to get her attention. Another plot twist could be that the kidnapper has a split personality, and one side is good and wants to free Raven, while the other side is evil and wants to keep her captive. And the last plot twist might be that Raven is kidnapped into a parallel universe where everything is different, and she has to find a way back while also dealing with the kidnapper in this strange new world.