Orube and Cedric is the "i can fix him" trope done right, and that's why this is one of the best romances I've ever seen in media.
The point is, that actually, Orube never intended to fix Cedric. She did it by knowing her truth and living it, even if that meant going against the one she fell in love with.
Orube showed a great trust and intuition when she turned to a person with a dark reputation loathed by her friends. That was quite a reckless thing, but intuitive things like that fit her somewhat feral nature. Throughout her character arc she had learnt how to be patient and resilient, had learnt the struggles of being a stranger in a foreign world and of staying true to herself no matter the circumstances. And the results of her growth have shown greatly in the Book arc.
But!!! As soon as Cedric showed the slightest suspicious signs, her mercy was over and she would never let her guard down after that. Orube wasn't trying to force anything towards Cedric, wasn't trying to be kinder and softer to him hoping to melt his rotten heart. As soon as he crossed a certain line, she knew she couldn't trust him anymore, although she had been ready to give him a chance. And this was a marvelous writing. After all, how often do we see a female character prioritizing her own values over a man? How often do we see a girl giving up on "fixing" someone who is clearly not ready for that yet?
And Cedric, as one of the main villains of the ceries, was also done justice here. He didn't have a face-heel turn and didn' really become 'good'. Yes, he couldn't think of hurting Orube and even aknowledged his feelings towards her, but this was a possessive and immature kind of feeling. All he wanted was just to have her by his side, without even taking her feelings and values into conscideration. His suggestion to join him in a fight against the Guardians was the PEAK of emotional blindness, and this basically sums up the nature of his feelings and his own character.
And the final change tbat Cedric has aknowledged at his deathbed didn't happen because of Orube's love and devotion to him. It was her resilience, honor and truthness that moved him. Unlike him, she knew exacly who she was and what she was fighting for, and she taught Cedric by example, not by becoming his allforgiving ally.
Conscidering all said above I don't know how to feel about fan versions about their romance rebound after Cedric miraculously survived. Is he really capable of getting over his power-seeking and villain-serving behavior? Would simple life on earth without superpowers and world-conquering ambitions satisfy him? And most importantly, would Orube, who knows her moral code and follows it religiously be able to forgive him? These are the questions left unanswered. And although I would love to believe in a happily ever after for these two, my outlook on their perspective as a healthy couple is not that positive.
Is this a healthy ship? Nope. Is it a good writing and character development? Absolutely! Is happy ending for these two even possible? This is a question I can't answer. It would be nice to see them as a power couple, but that would mean one of them completely abandon their old ways. Would any of them be able to do that? It's really hard for me to tell.
However, despite all above, these two have the sickest chemistry in the entire series without a single kiss. I've been obsessed with them for 10 years and can't get enough.