By the time you cross paths with Coron in the game, you're expecting her to be just another insane corpse come to life there to make your life worse. Yet, the worst thing she does is take the perfume. Then you learn she just wanted to be part of your family and, thinking back on the things she did, suddenly she seems like a bratty older sister.
I actually like Coron. She's kinda cute and I can get what she wants, which is basically that the curse run its course and suck everyone in. This sounds bad, but consider Coron's standpoint. The doctor was the one the wall message was for: "You said I would be family. You lied." But even though she was angry at the doctor, she never really hurt Aya. Just bullied her 'little sister', the favored daughter if you will, a little bit. Aya's mother would have seemed like family to Coron as well and, seeing as she brought the curse about, Coron would side with her, believing that by helping the curse be fulfilled, they would all be a family. Forcibly, maybe, in hell, but a family, which is what she wanted. In the end, Coron actually wanted the same thing as Aya, their family to be together and whole, just achieving it through different ends, Aya through staying alive and Coron by embracing death. It's really kind of sad.
Oh, and if you want to argue the dolls with me, since they want that too: burn them all. Yes, the dolls want Aya to be turned into one of them, making Aya part of their side of the family, as if shown by the argument heard where Coron is murdered, but literally to hell with that idea. Those things stab Aya to death in those dark sneaking areas. I'd rather side with the corpses.