The storyline could be extremely dark. Ruby, being raised by Salem, might be trained to oppose the Huntsmen and Huntresses. She could have a completely different view of the world, seeing the kingdoms as the 'bad guys' and Salem's side as the 'righteous'. Her relationships with her original friends would be in shambles as she would be on the opposing side. For example, her relationship with Weiss would be non - existent as they are on different moral spectra.
Her Semblance could be more destructive. Instead of using it mainly for mobility and quick attacks, it might be used to cause widespread chaos. For example, instead of just dashing in and out of battles, she could use her speed to create tornado - like effects that cause more damage to her enemies.
There could also be other characters who play important roles. For instance, Ruby's friends from Team RWBY, like Weiss, Blake, and Yang. They might be suspicious of Salem's intentions towards Ruby and try to protect Ruby from what they see as a threat. Also, Salem's minions could be in the story, and they might oppose Salem's newfound feelings for Ruby.
One interesting fanfiction could be where Ruby has to face Salem alone in a battle of wits and strength. In this story, Ruby might discover a new power within herself to counter Salem's dark magic.
I'm not sure specifically as there could be many different takes in such a fanfiction. It might involve Ruby growing up under Cinder's influence, which could lead to a complete change in her character, values, and fighting style. Maybe Cinder has some ulterior motives for raising Ruby, like using her as a weapon or a pawn in her grand scheme against Beacon Academy and the other Huntsmen and Huntresses.
I'm not entirely sure as it could vary greatly depending on the author's creativity. It might explore how Ruby's character would develop if she was raised by Grimm. Maybe she would have a very different set of skills or a darker personality.
It could be about Ruby being raised by Weiss instead of her usual upbringing in the RWBY world. Maybe it explores how Weiss's family environment and values shape Ruby's growth and development.
Perhaps Salem starts to change her ways because of her love for Ruby. She might begin to question her long - held beliefs and actions, which could lead to a lot of drama and conflict within the story. For example, her followers might not understand her new attitude.
If Ruby joins Salem in the fanfiction, it could be a very dark turn for Ruby. Salem might manipulate Ruby into believing that her methods are the only way to bring about a new order. However, Ruby's friends would never give up on her. They would try to rescue her, and in the process, Ruby might have a change of heart and turn against Salem, leading to an epic showdown.
One possible plot could be Ruby Rose trying to understand Salem's motives. Maybe Ruby, with her pure heart, believes there's a chance to redeem Salem. She could engage in a series of intense conversations with Salem, where Ruby tries to appeal to any good that might still be in her. This would be a great exploration of the themes of good versus evil and redemption.