Wind: A Breath of Heart (TV) EP11 - Destiny from the Ancient Times

Makoto finds Hikari at the temple and she decides to tell him everything when he says he wants to find a way for everyone to be happy. Apparently, in ancient times Hikari was just a normal priestess. When she saw the ritual sacrifice being done she could not handle it and so set the temple on fire. When she was about to kill the man she thought responsible (her own brother), he said he was free from the curse but that Hikari would have to take over. And so she has been killing to protect the town ever since. Makoto still believes everyone can be happy though and follows Hikari when she runs off. She asks him to save her and then jumps off the edge of a cliff, he follows her to catch her.