Mielle is such a tragic character. Because even with Aria intentionally drawing things out for more sweet revenge, it created numerous chances where she could've genuinely changed. And after killing her brother, she almost was on the cusp of it.
But instead she chose to double down on it, tragically, only perhaps at best having some clarity in death.
In a alternate world, Aria even out for vengeance, would've had mercy if Mielle would've repented and their relationship could've been repaired. She still would have to live with her consequences,but she could've lived a humble life.
Initially I really disliked Aria. She was vindictive and petty(though she had 100% justification)(I don't think it is right to punish someone for something they haven't actually done, especially without at least extending one last olive branch).(it is not completely unlike bullying the bully, 2 wrongs don't make a rignt)
But as time grew on Aria abandoned her proper plotting, and just focused primarily on amassing wealth and power to survive, rather than getting back. Letting Mielle and others dig their own holes, they could've easily avoided if only they repented.
Aria earned my respect as the series progressed, showing remarkable restraint. And then, even if it was expecting Mielle to finish herself off, Aria seemed to genuinely give her chances. Even egging Mielle on to "prank"(poison) Annie, seemed like it was pushing Mielle to a crossroads. One where Mielle could determine those actions are wrong, and not follow through. They may never repair the relationship between them(certainly there is negative obligation to even try), what Mielle already had done was way too much. But had Mielle turned her ways, it could've become a good conclusion where they come to a mutual understanding, where she lives a quiet humble life, and perhaps genuinely appreciates the chances.
In the end, I would still critique Aria in one way. Letting the Brother die like that, when she specifically was prepared to save a life, was ice cold, particularly because she was responsible for him being alive, and even being there to drink poisoned tea in the first place. She was the one who gave him a chance, and he genuinely seemed to accept it and was repenting. She literally had the ability to save him easily, but didn't, even after his and Mielles true colors were shown there. And Mielle still could've been beheaded for attempted murder.
It was like the ethical trolley dilemma, only the train is heading towards one person, and all the other person had to do is pull the lever and a life is saved for free.
It just would've been nice if one of the family could have properly changed their ways and live their life. Just like there can be life that is worse than death, a person living their life repentent can be better than death.
But in the end,it is great Aria can live a happy life. She certainly deserves it.