One interesting plot could be Ruby and Kaneki swapping places. Ruby finds herself in the Tokyo Ghoul world, trying to survive with her scythe skills against the ghouls. Meanwhile, Kaneki ends up in Remnant, learning about Huntsmen and Grimm. Another plot might involve teams RWBY and some of the Tokyo Ghoul characters teaming up to fight a common enemy that threatens both their worlds. For example, a powerful Grimm - ghoul hybrid created by a mad scientist.
Ruby's speed and scythe - wielding skills could be combined with Kaneki's kagune attacks. For example, Ruby could use her speed to quickly dodge an enemy's attack and then Kaneki could follow up with a powerful kagune strike. Weiss's glyphs could be used to enhance or control the movement of a ghoul's kagune. Blake's shadow clones could be used to confuse the ghouls while the Tokyo Ghoul characters attack from different angles.
Another concept is a crossover of the powers. In the fanfic, Weiss could have some sort of ice - based kagune, which combines her Schnee family glyph powers with the unique abilities of a Tokyo Ghoul. Blake could use her shadow powers in a way that is similar to how ghouls move in the shadows, making her a more stealthy fighter in the Tokyo Ghoul setting.
First, do your research on both universes. Know the characters, their powers, and the settings well. For RWBY, understand the different academies, the concept of Dust, and the relationships between the main characters. For Tokyo Ghoul, learn about the CCG, the different types of ghouls, and the Anteiku coffee shop.
Well, for a Tokyo Ghoul fan, reading fanfiction while being a fan of the original can be a mixed bag. On one hand, it's exciting to see how other fans' creativity expands the world. For example, there could be fanfictions that focus on the backstories of minor characters. However, sometimes the quality can vary. Some might not capture the essence of the Tokyo Ghoul world as well as others. But overall, it gives a chance to delve deeper into the fandom.
Power struggle is a common theme. You have the super - powered beings from Prototype and the ghouls from Tokyo Ghoul, all vying for control or survival in a merged world.
Some fanfictions crossover Tokyo Ghoul with Naruto. The idea of ninjas and ghouls in the same universe is really cool. The shinobi could be trying to hunt down the ghouls, or there could be some sort of alliance formed between certain ghouls and ninja clans. It offers a lot of potential for action - packed and character - driven stories.
The plot could involve a shared threat that forces the Tokyo Ghoul and Parasyte universes to collide. Maybe a new type of organism emerges that is even more dangerous than ghouls or parasites. The characters would then have to combine their unique abilities to combat this threat. For instance, Kaneki's kagune and Shinichi's enhanced physical abilities with his parasite Migi could be used in tandem. This would create an interesting dynamic as they try to figure out how to work together while also dealing with their own internal struggles related to their inhuman natures.
One great Tokyo Ghoul Kaneki crossover fanfiction is the one where he crosses over with the world of 'Attack on Titan'. It's really interesting to see how Kaneki's ghoul abilities interact with the Titans. The author does a great job of creating a believable scenario where the two worlds collide.