Blake might be a bit more reserved in her reaction. She would observe Ruby carefully, trying to understand how to best help her. Blake has a more introspective nature, and she would likely think about the long - term implications of Ruby being deaged. She might also share some of her own experiences of feeling lost or different to help Ruby cope with her new situation.
Weiss would probably be very protective at first. She has always had a bit of a mother - hen side to her, and seeing Ruby in a more vulnerable, deaged state would bring that out. She would likely try to keep Ruby out of trouble and make sure she was taking care of herself.
One idea could be Ruby having to relearn her combat skills while being deaged. It would add an element of struggle and growth as she tries to regain her former abilities. Maybe she forms new friendships with characters she already knew in a different way because of her new, younger perspective.
At first, Batman would be shocked and a bit confused. But quickly, his detective instincts would kick in. He would view the deaged Joker as a new and unexpected threat. He'd start gathering information about how the deaging occurred, in case it was part of a larger, more sinister plan. Batman would also be very careful not to underestimate the deaged Joker. He might try to isolate the Joker in a secure location to prevent him from causing chaos in Gotham. And he'd be constantly on the lookout for any signs of the Joker's old, devious self emerging from this new, younger form.
Ruby is often a popular choice. Her innocent and determined nature can be explored in new ways when she's deaged. Fans like to see how she would interact with the world around her with a child - like perspective while still having that spark of heroism.
One character that would be really interesting to pair with deaged Loki is Doctor Strange. Strange could be the one to help Loki figure out how to reverse the deaging process or use his new situation to his advantage. Also, if we consider the Avengers, Natasha Romanoff could be paired with deaged Loki. She could teach him some skills that he might not have learned in his original upbringing, like stealth and espionage. And Steve Rogers could also be a good match. Rogers' sense of honor and justice could have an impact on deaged Loki and maybe even inspire him to be a better person.
Well, her sister Yang would definitely be one of the main characters. Yang would be very protective of Ruby and would try to help her in any way she could. Weiss would also be important. She might use her intelligence and Dust - related skills to assist Ruby. And Blake, with her stealth and combat skills, could be crucial in protecting Ruby and guiding her through difficult situations.
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.
Blake is also a common character to be paired with Ruby. There could be fanfictions where they team up for a special mission that is different from the main storyline. For example, they might have to infiltrate a secret organization together, relying on each other's unique skills.
One character could be Nora. Nora is energetic and fun - loving, just like Ruby in some ways. Their combined energy could make for a very lively threesome scenario in fanfiction. Ren might also be a candidate. Ren's calm and collected nature would contrast well with Ruby's more exuberant personality. Together with another character, perhaps Weiss, they could form an interesting threesome. Also, Emerald could be in a threesome with Ruby. Emerald has her own motives and a somewhat complex personality. Her interactions with Ruby, especially in a threesome situation, could add a lot of depth to the fanfiction.
In some cases, new original characters might be introduced. These could be other hunters or huntresses who have a connection to the source of Ruby's darkness. They could either be helping Ruby or be part of the problem. Maybe they are also victims of the same dark power that is corrupting Ruby and they both have to find a way out together.
A great plotline might involve the deaged characters interacting with their younger selves' memories. Weiss could be haunted by her family's expectations in a new light, as if seeing them for the first time all over again. This could lead to her making different choices and growing in a whole new direction.