Maybe there's a character who discovers they have the power of a puppet master accidentally. They struggle with this new power as they don't want to use it to control others but at the same time, they realize it could be useful in certain situations. This internal conflict could drive the plot as they decide whether to embrace or reject this power.
A possible plotline could be that a new enemy emerges in the RWBY world, a puppet master who starts to take over the minds of the hunters and huntresses. The RWBY team has to figure out how to stop this enemy before everyone they know becomes a puppet under the enemy's control.
The 'rwby puppet master fanfiction' might also explore the theme of free will. When characters are being controlled like puppets, it challenges the idea of free will in the RWBY world. How do the other characters react to this? Do they try to break the control? And how does the puppet master's power affect the overall balance of power in the RWBY universe?
Perhaps there is a common enemy that forces Captain America and the RWBY characters to work together. This enemy could be a powerful being that has the ability to manipulate both the technology in Captain America's world and the Dust in RWBY's world. The combined forces of the two universes would have to find a way to defeat this enemy and in the process, learn from each other's strengths and weaknesses.
Maybe a plot where Glynda's telepathy is somehow affected by an outside force. This could lead to her losing control over it at times and causing chaos, and she has to find a way to regain control and fix the problems it causes. It could also involve her learning more about her own power through this struggle.
One possible plotline could be that Ruby is kidnapped by a powerful new enemy. This enemy might be after her silver eyes power and plans to use it for some evil scheme. Another could be that Ruby accidentally gets transported to another dimension during a battle, leaving her team to search for her.
A plotline could involve Si's genderbent self having to prove themselves in a world that may have different perceptions of their new gender. They could struggle with how others view them and at the same time, discover new aspects of their own abilities. Maybe they were underestimated in their original form, but as a genderbent character, they show everyone what they're truly capable of. It could also involve a romantic sub - plot where their new gender changes the dynamics of their relationships with other characters in the RWBY universe.
Well, it could involve the RWBY characters seeing future versions of themselves. Maybe they see how their relationships have evolved or how their combat skills have improved. They might also witness future threats to Remnant and start preparing for them in the present.
Well, a possible plotline could start with Ruby being somehow infected or cursed to become a Grimm. She would then experience a whole new set of emotions and abilities. Maybe she starts to have visions or dreams related to the Grimm's origin or their purpose. As she tries to understand what has happened to her, she might be ostracized by some of her friends who are afraid of her new form. However, a few might believe in her and help her. She could then try to use her new Grimm - like abilities, such as enhanced strength or stealth, to fight against a greater evil that is threatening both the Grimm and the people of Remnant. Along the way, she could learn more about the true nature of the Grimm and find a way to either reverse her condition or fully embrace it in a way that benefits everyone.
Perhaps a plotline where the values that Mao Zedong represented, like equality and the fight for the common good, are transferred to the RWBY universe. The RWBY characters could be inspired to fight not just for themselves but for all the people in the kingdoms. They could start new initiatives like ensuring equal access to training for all those who want to be huntsmen or huntresses, similar to how Mao Zedong fought for the rights of the common people in China.
Another plotline might be that Jaune is framed for a crime he didn't commit and decides to disappear to clear his name. He goes into hiding and starts his own investigation, all while his friends in RWBY are trying to figure out what really happened and whether he's actually guilty or not.
One possible plotline could be Naruto trying to protect Nora from the threats of the Grimm while also teaching her some of his ninja skills. Another could be Nora growing up with a split identity, feeling part of the RWBY world but also having a connection to Naruto's ninja heritage. Maybe she would struggle to fit in at Beacon Academy because of her unique background.