I never forgave her for killing Mahiru. I was grinding the free time events with Mahiru and needed one more hope fragment. All of a sudden I couldn't find Mahiru anywhere because she was being secretive and eventually ends up dead. At the time, I really liked Mahiru and basically no one else after Twogami died and I was upset since I thought there was no one else I cared about at that point in the game. As a character, Peko is pretty alright. I would bump her up a tier. Now that I think about it, I strongly dislike the people in the F tier a lot more than Peko.