When Ashiya begins working part time at the Mononokean, the master Abeno impresses upon him that he should pretend not to see any yokai other than the Mononokean's clients. However, the kind-hearted Ashiya is unable to keep his word, and the yokai won't leave him alone. Based on their surprising strength and numbers, Abeno believes there must be a powerful demon serving as their leader.
But you said yokai belong in the Underworld.
Aber du meintest doch,
Yokai gehören in die Unterwelt.
Pero dijiste que los yokai
pertenecen al inframundo.
Mais t’as dit que leur place
était dans le monde caché…
Mas você disse que o lugar
 dos yokai é no submundo.