Even after Camio reveals himself, William remains concerned only with his grades and tuition and tries to distance himself from the demons and their political war.  Unfortunately, he soon finds himself roped into another problem when the Headmaster asks him to find the source of a mysterious singing voice that's been disturbing students late at night.
Then why didn't you recognize him as one?!
Entonces, ¿por qué no lo reconociste?
Entonces, ¿por qué no lo reconociste?
Então por que não 
reconheceu logo de cara?!