This is interesting, judging by the marking on the eye of the figure above this is Kurona.
But also judging by the image below Kurona and Nashiro are either both there.
Or Kurona may have went mad after Kanou probably gave her her sister’s kakugan eye. So she feels like she’s right there…(He used Nashiro for parts when he deemed her unsaveable…)
Or maybe somehow, she did it herself… out of grief…