Didn't Clairen die in Book 0?
Starting here and over the next two pages, it's difficult to see how Clairen can have survived being turned into a pile of ashes...
But was she turned into a pile of ashes?
As literally every character said in that one ep of Psych, no body no crime.
Plus, I don't know if you read the Buffy comics, but the exact same thing was recently done to one of the characters, engulfed in flames, only see a dark shape within the flames, and then nothing left but a pile of ashes. When actually they hadn't been hurt at all, just made temporarily invisible.
I too thought it was Mary at first, but now I'm leaning towards Clairen.
I mean looking at what we see of this character, the smirk, the lip bite, the slightly upturned drawn now, all aspects of Clairen's design. Plus there's the fact that we only get shown one arm, the one that we know Clairen still has. Sure she probably would of regrown the other by now, I'm just saying, the only time we're shown one of this characters arms it's the one Clairen didn't lose.
Plus this story has all been so centralized on Bern's past in Marvallo, so it wouldn't make much sense for it to be Mary. Plus she doesn't have the scars.