When Ruby dies in the fanfic, the reactions of the other characters are complex. For example, Nora and Ren, who are friends of Team RWBY, would be heartbroken. Nora might become uncharacteristically quiet, while Ren would try to keep his emotions in check but be visibly shaken. Jaune would feel like he has lost a guiding light. He had always looked up to Ruby, and her death would make him question his own leadership skills. The students at Beacon Academy would also be affected. They would hold memorials for Ruby, and some might be inspired by her sacrifice to become better Huntsmen and Huntresses, while others would be too afraid to continue their training, fearing a similar fate.
The other members of Team RWBY would be deeply affected. They would start to question their own abilities and the purpose of their fight. Some might withdraw into themselves, like a broken Weiss who shuts out the world for a while. Yang, on the other hand, could become reckless in her pursuit of vengeance, endangering herself and others. Blake would try to hold the team together, but she would also be mourning privately. The other friends and allies in the RWBY universe would also be in mourning. Qrow might blame himself for not being there to protect Ruby, and Ozpin would see it as a great setback in the fight against evil.
Ruby would be devastated. Qrow is her uncle and has been an important figure in her life. She might initially go into denial and then be filled with rage, vowing to avenge his death. She could become more determined than ever to take down Salem, seeing it as the only way to make his sacrifice meaningful.
Ruby would be deeply saddened. She might blame herself for not being able to protect Blake. Weiss would probably be in shock at first, then become more determined to fight against whatever caused Blake's death. Yang would be furious and seek revenge. She has a very close bond with Blake, and her death would likely fuel Yang's anger towards the enemy.
Hermione would likely be devastated. She might go into a deep state of mourning, but also use her intelligence to try and figure out what led to Harry's death. Ron would be angry and heartbroken at the same time. He'd probably want to seek revenge if there was someone or something responsible.
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.
Optimus Prime might be deeply affected. He would probably feel a great sense of loss, as Arcee was one of his loyal soldiers. He might give a solemn speech about her bravery and sacrifice, while also mourning privately.
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.
Winry would be heartbroken. She loves Edward deeply. She might initially go into denial and then be filled with anger at the circumstances that led to his death. She could also turn her grief into a determination to help others with her mechanical skills, in memory of Edward.
Sasuke would be deeply affected. He and Naruto had a complex relationship. He might feel a sense of regret for all the times he had pushed Naruto away. His reaction could range from anger at the situation to a new - found respect for Naruto's sacrifice.
Yang would be completely heartbroken. She'd likely go through a period of intense grief and anger, possibly even blaming herself for not being able to protect Ruby. Weiss would be deeply affected too. She might become more reserved and solemn, vowing to use her skills to uphold Ruby's ideals. Blake would be inspired by Ruby's sacrifice to be more active in fighting against the darkness. She might see it as a call to arms to make Ruby's sacrifice not be in vain.
Nagisa would be completely devastated. She has a very deep connection with Tomoya, and his death would likely cause her to sink into a deep depression. She might even lose the will to live, especially if it happened suddenly. For example, if he died in an accident, she would be left with a sense of emptiness and longing for him.