silo's manga / #school life(4)

I was counting how many demons are here but there were only 16 (12 classmates + 4 adults + Amelie = 17), I'm missing one. Then noticed there is a spot that is blank in the middle and remembered they have a classmate that can disappear. hehehe so he must be there. https://www.mangago.me/read-manga/mairimashita_iruma_kun/nbt/nhs_v-4-chapter-833492/pg-1/ Mystery solve