In chapter 33, it is revealed that Eirin knew very well how much she hurt Rin, and has felt like a monster for all the nine years after her imprisonment. Oh, and Rin is only the latest in the list of Eirin's experiments that have Gone Horribly Wrong. Up until then, she's been a total jerk to everyone, especially Reisen, and of course the Rin Satsuki Experiment is more than enough of a reason to hate her, but damn, you can't help but feel at least a little sorry for her when she says that she's beyond redemption and knows it, and just wants to rescue Kaguya before facing her rightful punishment. Goes to show that even the JerkassMad Scientist has a conscience and could actually have been a decent person if only her passion for her work hadn't always had horrible consequences for everyone around her.
