Karharot said:
Well, at that point Riful had barely enough yoki left to keep standing (those are her thoughts not my speculation), that certainly isn't something worthy of notice to Priscilla who seems to have infinite reserves of it to begin with.
Back then it looked more like Priscilla was just her usual not-entirely-up-there self and tried to eat Riful guts because she was hungry (and because Riful dared to attack her in Dauph defense) but it was a little strange considering that just before going to Riful she made several attempts to convince Beth to get lost (and killed her only because twins would not stop pestering her) and then she went to Riful and killed her pretty much only because Dauph tried to verbally intimidate her. It was not really out of character for Priscilla to do something like that (she always does what she wants to do at the moment) but it was still a little strange (she just picked on Clare after 7 years of searching, she was clearly in a hurry which she stated to Beth, so why did she lose her time on Riful who clearly was not willing (or even able) to bother her?
I very desagree with you :
When Pricillia met Clare, Helen, and Deneve in the chapter 100, she said that she was hungry, so I don't think she attacked Riful for her pleasure, she did it to steal her energy. And in the chapter 99 she said the Riful's flesh has a bad taste like Cassandra said when she ate Roxanne.