Within the World - S1.E8

Shinichirō gets Saya to tell her about the Furukimonos, offering to be her confidant. As Saya returns home, she finds Tadoyoshi collapsed on the floor, though he passes it off as a dizzy spell. As the dog talks to Saya, asking her what would happen if she broke the promise she made, she experiences another headache as she recalls something concerning a reward and a punishment. After a few days of no Furukimono activity, Saya returns to school, where a Furukimono appears and attacks the class, killing several students. With no escape available, Saya is forced unsheath her katana in front of her friends to fight the Furkimono.