RRBW: Cinder Fall
I'll admit, seeing Cinder nervous around Sonic and Shadow has some appeal, and a fight between her and Blaze could be interesting. But that's where the positives end. Honestly, the way this fic handles Cinder is just depressing. She's given such a raw deal in this AU that it's hard not to feel sorry for her.
In canon, Cinder always found ways to stay ahead and maintain control. Here? She gets systematically destroyed during the Vytal Arc. Tails wipes out her virus program, Sonic lures her into a trap and captures her, and even after she escapes with the full Fall Maiden powers, Shadow brutally beats her down. By the Battle of Beacon's end, Cinder is the sole villain who fails to escape. She's captured, hospitalized in a coma, loses both arms and an eye, and even if she wakes up, she'll be permanently crippled. The cherry on top? She loses the Fall Maiden powers when the Grimm containing them is destroyed.
Complete Failure: Everything Cinder worked for—all the scheming, all the killing—ends up meaning absolutely nothing. She finally obtains the full Fall Maiden powers only to get completely demolished by Shadow, proving that even with everything she wanted, she's still powerless. Super Sonic removes the Grimm inside her, and with it goes the Maiden powers. Her entire arc accomplishes nothing except leaving her broken and disabled.
The injuries are extensive. Shadow tears off her right arm during their fight, then removes her left arm after Super Sonic deals with the Grimm, leaving her with no arms at all. Her left eye is destroyed when Shadow unleashes his full power. The damage to her internal organs is so severe that Atlas doctors have no choice but to gradually convert her into a cyborg. In canon, Cinder loses an eye and arm but gets replacements. Here, she loses both eyes, both arms, and suffers catastrophic internal damage that requires complete cybernetic reconstruction.
Why This Is Problematic: The level of violence Shadow inflicts on Cinder is excessive and unjustified within this story's context. Yes, canon Cinder commits terrible acts, but in this fic, Eggman and Metal Sonic have taken over nearly all her villainous roles. Her only actual crime here is killing one White Fang member who planned to defect. That single act doesn't justify Shadow maiming her this brutally. What makes it worse is that Eggman and Metal Sonic—who've done far worse in this story—escape the Fall of Beacon relatively unscathed. The disparity suggests the author is punishing Cinder for her canon crimes rather than what she's actually done here.
Wasted Character: Out of all the mishandled characters, Cinder suffers the worst treatment. Across the entire Vale Saga—30 out of 40 chapters—she's constantly defeated by the heroes and berated by Eggman for minor errors. Her arc climaxes with her being captured before the Battle of Beacon properly begins. Even when she obtains the Maiden powers, Sonic and Shadow demolish her immediately. The aftermath strips away her powers, leaves her permanently disabled, and Salem marks her for death on sight (though given her condition, that's unlikely to matter).
The biggest villain in RWBY besides Salem herself has been reduced to a completely ineffective antagonist with zero agency. She has no meaningful presence going forward and never even interacts with the main RWBY protagonists. All her canonical relationships and significance have been erased.
It's telling that Jaune directs more hatred toward Qrow and Ozpin than toward Cinder.
Beyond her enemies, even Cinder's allies despise her. Eggman sees her as an arrogant nuisance, and Salem eventually deems her worthless, ordering her faction to execute her if they find her alive.
Cinder follows Iron117Prime's pattern of powerful villainesses from the original series getting destroyed by crossover heroes—similar to Azula and Cornelia li Britannia. The critical difference? Those characters had redeeming qualities and eventually joined the heroes. Cinder has none of that depth, but she also hasn't been given the chance to earn such brutal punishment.
Future Possibilities: A few paths remain. Unlike Prime's previous stories, Cinder won't redeem herself. At best, she might temporarily ally with Ruby and Sonic purely to get revenge on Salem for abandoning her—and if she betrays them, Sonic will let Shadow finish the job. Alternatively, another villain faction could rescue and recruit her. Or she simply gets killed off by Salem's forces and forgotten entirely.