Hata no Kokoro is the final boss in Hopeless Masquerade final stage. She is a Menreiki youkai. Youkai means demon in English.
As a Menreiki Youkai, Kokoro has more than 66 masks. The 66 masks were used by the the father of Sarugaku performance, Hata no Kawakatsu.
Prince Shoutoku ordered that Kawakatsu perform 66 types of play for ancient ritual with 66 masks given by him to end the war. After they play were enacted, the war ended.
Kokoro is a character from Touhou Project’s pc game that started back in the year of 1995 by Team Shanghai Alice. The company has then made many pc games version of the series with the first one were made for NEC computers.