Can't find where the memory card's supposed to be on my phone and Dr. Google is being vague with me... :(
Diva (Blood+): Purposely had the Chiropterans and some rouge forces to go against Saya in hopes to kill her ever since the rampage she caused after the event where Saya went to meet her in person despite the experiment that both were unaware of. Alongside some other deaths that she caused, she also rape-murdered one of Saya's chevaliers and voluntarily got pregnant from it.
Mion Sonozaki (Higurashi Saga): In one of the arcs, she was behind a string of murders following the events after a trip to a forbidden part of her family's shrine during the Cotton Drifting Festival. She even had to torture Shion and some of the others (including herself) along the way.