Promise

Promise

Available on Prime Video, Crunchyroll
S1 E6: Shinichirou tries to cheer Sakuya up after he finds out that she might lose her right to become next head of the family. The secret behind Sakuya's birth, and why she's so hung up on taking over the family becomes evident. But then a monster shows up which will test her allegiances to the past, to the present, and to herself.