Yayoi is a girl obsessed with the occult stemming from her desire for revenge on Kuubo for taking her mother's spirit. She will do almost anything to save her. That includes using any kinds of ghost, even if they are extremely evil.
Despite this obsession she has a strong moral compass. She will punish ghost that have killed many people, but she will be kind to those who unwillingly became corrupted. She knows that what she is doing is dangerous and will always put the safety of others as her top priority. She loves her friends and family dearly and has a strong desire to protect them.