Hanyou no Yashahime: Sengoku Otogizoushi - Ni no Shou

Synopsis

While Setsuna goes to retrieve the root, Moroha asks Jyuubei about Bokusenou, by finding a demon with wisdom and mystical demonic abilities. Moroha accompanies Setsuna to find it but ends up encountering the snake-demon spirit disguised as a human nun, who desires Setsuna's waist-length hair to appease her intense fury and bitterness at never being able to restore her true form. Towa arrives in time to aid a group of demon-slayers, wearing a pair of mirrored sunglasses to protect everyone from turning into petrified statues. It is then that Setsuna realizes she can put an end to all of this suffering. She utilizes her Yukari no Tachikiri's strongest and most useful ability to cut all physical and immaterial things/beings, both seen and unseen, to restore the destiny of the snake-demon and that of her human love, a fisherman. Finally at peace with herself and the humans on the surface, the Snake-Demon manages to regain her true form and returns to her home in the sea. The Half-Demon Princesses leave on Takechiyo, with Riku watching from a distance; glad that Towa is safe and that he awaits their next encounter, during which Towa would be wielding a genuine weapon fully empowered with immense demonic energy against the siblings.

(Source: Wikipedia)