Oni (demons) symbolize the "negative emotions" that live inside people.
There is a traditional Japanese event of throwing beans to drive away the “ONI” in people's minds.

ONI girl. The meaning of the black ONI is "doubt". She covers her mouth with a raven mask and doesn't say a word about her doubts. She wants to believe. What will she say when she takes off the mask?
People can protect themselves by doubting......