Ruby's combat skills would be more focused on stealth and ambush. Salem would likely train her to be a more sneaky fighter. So, instead of the head - on combat style we see in the original RWBY, she would be more like a shadow, striking when the enemy least expects it. Her weapon Crescent Rose could also be adapted for quieter attacks, like having a silencer - like mechanism.
If Ruby was raised by Salem, her abilities would be more in tune with Salem's goals. She might gain the ability to manipulate Grimm in some way. Since Salem has a connection with the Grimm, she could teach Ruby to use them to her advantage. Ruby's physical strength might also increase in a more unnatural way, perhaps enhanced by some dark magic that Salem uses, which would change the way she fights and interacts with her opponents.
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.
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.
With Yang, their relationship would likely be less of a sisterly, protective one. Since Goodwitch would be in a parenting role, Ruby might not rely on Yang as much for protection. Yang might also see Ruby as more independent and grown - up, which could lead to a more equal friendship.
A major difference could be in her leadership style. Ruby, when raised by Summer, had a more instinctive and inspiring leadership. But with Winter, she could be more of a by - the - book leader. She might rely more on established military strategies rather than her gut feelings, which could both be an advantage and a disadvantage depending on the situation in the story.
She might be more guarded. Qrow is a cautious person, and if he raised Ruby, she would likely pick up on some of his wariness. So instead of being as open and naive as in the original series, she could be more hesitant to trust new people right away.
The other characters would be shocked. Weiss would probably be the first to try and figure out what's wrong with Ruby. Blake would be worried about Ruby losing her way, and Yang would be furious. Yang might even go on a solo mission to bring Ruby back, not fully trusting the rest of the team to handle it delicately. The rest of the characters like Jaune and Nora would also be in disbelief and would start planning ways to rescue Ruby.
His chakra control would probably be better. In a temple, he might learn meditation techniques that help him master his chakra more effectively. Also, his physical abilities could be more refined in terms of balance and grace, like a monk's movements.
His water - based abilities would likely be more refined. Amphitrite could teach him advanced techniques for controlling water, like creating complex water formations or using water for long - distance communication. He might also have a better understanding of the magic within the sea, being able to tap into hidden powers that normal demigods wouldn't know about.
Mentally, Harry would be more in tune with the Force. This would give him an edge in sensing danger and the intentions of others. His ability to resist the Imperius Curse might be stronger due to Jedi mental training. Instead of using spells for divination, he could use the Force to foresee events. And his telepathy - like abilities from the Force could be used in place of some magical communication spells.
Naruto's combat style would be more refined. Sakumo was a highly skilled ninja, and he would teach Naruto better swordsmanship skills perhaps. Naruto's taijutsu could also be more precise and calculated. Also, Naruto might develop better chakra control earlier, as Sakumo could instill in him the importance of efficient chakra usage from a young age.
Well, with Ruby's friends like Weiss, Blake, and Yang, their relationships would be strained. They'd be skeptical of RWBY's loyalty as they were raised by Salem. For instance, Weiss might be more guarded around RWBY, not fully trusting her motives anymore.