Her name is "Eua" - Higurashi Gou
A woman with horns similar to Hanyuu. She likes to call Rika "cat".
In exchange for letting her behold, she grants Satoko the power to live in loops. She calls herself Eua after Satoko, but her true identity is completely unknown.
https://higurashianime.com/chara14.html
Rembember to turn on english subs
ひぐらしのなく頃に業 (Satokowashi-hen)(Episode 23)