Well, there could be an arc that focuses on the political aspects of the RWBY world in fanfic. For instance, how different kingdoms interact, their treaties, and the power struggles between them. This could involve characters getting caught up in diplomatic missions or trying to prevent a war between kingdoms. Another interesting arc would be a survival arc, where characters are stranded in a dangerous area, like a Grimm - infested wilderness, and they have to use their skills and teamwork to survive. And then there's the arc of a character facing their fears. This could be a fear of failure, a fear of losing loved ones, and how they overcome it through various challenges in the fanfic.
One interesting arc could be a character's journey to master a new weapon or semblance. For example, a fanfic might explore Ruby's attempts to combine her scythe skills with some new form of long - range combat. Another arc could be about team building within RWBY or other teams in the fanfic's universe. It might show how characters with different personalities and abilities learn to work together more effectively. And then there could be an arc centered around a mystery, like uncovering the secrets of an ancient relic that has a big impact on the RWBY world.
In RWBY fanfic, a great arc could be the redemption arc of a villain. Maybe a character who was once on the side of evil realizes the error of their ways and tries to make amends. This could involve them helping the heroes in their fight against a greater threat. Another arc could be a love triangle arc. Characters in RWBY have complex relationships, and a fanfic could explore the tensions and emotions that come with a love triangle situation among the characters. Also, an arc about a character's self - discovery is quite common. A character might question their identity, their place in the world, and what they truly want to fight for.