Zok had seen and done a lot of weird things ever since Wilderness became his home. But what he was seeing right now was completely unacceptable, even for him. Even the beasts that he knew of did not indulge in this kind of thing and yet this girl was enjoying feeding on her kin? Just what happened here in this cave?
'Maybe this girl is a shapeshifting monster?'
Since he was in a cave, that was his first thought. He didn't know about the existence of such a monster, but he was desperately looking for anything that could explain why the girl was eating people that looked like her. but the more he thought about it, the more he realised it wasn't possible.
However, he was aware that the caves sometimes could mess with the heads of those who enter them. Also, he knew about monsters who could mess with one's mind, thanks to the updated index. One of the twins knew about it and when he killed them, Zok took their knowledge for himself and thus knew about such a beast.