Natsume overhears whispers that a powerful youkai is reviving, later that evening he is trapped in a bottle as an offering.  Humans can’t see or hear him, so Nyanko-sensei decides to help the “best” way he can…
They're fundamentally different from humans.
Básicamente los ayakashi son 
diferentes a los humanos.
Te he dicho muchas veces que los ayakashi son muy diferentes a los humanos.
Eles são diferentes dos humanos.