I honestly feel bad for Elya. Like, sure, she's a truly despicable person, just like the rest of them. She was fully willing to kill the MC for the sake of saving some money, and even before that she mistreated him like the others did.
But her karma for it, the unique skill that she lost, is the loss of her intellect. For the rest of them, their unique skills are just special abilities or extreme durability, but hers is more closely tied to who she is as a person.
In losing her skill, she's lost part of her ego (in the psychology sense, not the pride sense). She's lost part of her sense of self.
I wouldn't wish that on anyone.
The rest of them are gonna have to deal with the consequences of their actions, but at least they'll have the capacity to understand those consequences.