Episode 12 (Hanyō no Yashahime)

Night of the New Moon and the Black-Haired Towa is the twelfth episode of Hanyō no Yashahime.

Synopsis
Konton of the Four Perils sends another half-demon, Nikosen, after the trio in hopes of destroying them and attaining their Rainbow Pearls. While fighting a demon that had withered an entire mountain. Towa comes to realize that she is suddenly much weaker and has her silver hair turned black to match her twin's. It is up to Moroha and Setsuna to take down the enemy until Towa's demonic powers return.

Plot
In his cave lair, Konton of the Four Perils has a sage-turned-apparition demon named Nikosen the task of annihilating the Half-Demon Princesses and attaining their Rainbow Pearls. At the village, Kohaku tells Towa and Setsuna about how an entire mountain has been withered with poison by Nikosen himself. Towa is excited but Setsuna is uninterested and will only slay the demon only if it is ordered by Kohaku, which she accepts. Moroha has come to help the local villagers in destroying the demon and claim another gold ingot from Jyūbei. Towa and Setsuna come to join her but are attacked by Nikosen who demands the Rainbow Pearls they possess. Towa attempts to join her twin sister and cousin in battle, but her light blue energy blade does not form, which concerns her and puzzles Setsuna, as she can hear her heartbeat louder than she should. Moroha tries to use her Kurikaramaru but is unable to slice through Nikosen. In retaliation, Nikosen sends forth a stream of poison that affects and weakens Towa. Setsuna gives her a poison-shielding mask and tells Moroha to take care of Towa while she fights the demon.

As Moroha helps an unconscious Towa across a bridge, she notices the change in Towa's hair color and length but is blocked by Nikosen's torso. In midair on Kirara, Setsuna attacks an illusion of Nioksen's head which is undo by the assistance of Hisui and his fellow Demon-Slayers. Finding shelter in a cave, Moroha is surprised that she smells the sent of human on Towa. Knowing that she has to fight with Setsuna, she prepares to use her paternal grandmother's rogue and give Myōga a good meal of her grandfather's blood. The flea demon then appears and explains Towa's predicament is because it is the night of the new moon which is different for every half-demon, with the exception of the late Naraku who was capable of choosing a night of his own free will. Towa is concerned that Setsuna has experienced the exact same transformation and wants to go find her.

With aid from Myoga, Moroha infuses her spiritual powers into sutras to erect a blue sacred barrier to protect Towa. As Setsuna retains her full abilities, Moroha deduces that because her memories were taken from her by the Dream Butterfly, the laws of the new moon no longer apply to her. Taking advantage of this fact, Setsuna manages to hold off Nikosen who hopes to eat her and gain strength from her. Fortunately, daybreak comes and restores Towa's dog-demon abilities, ending in her using her charged sword to wipe him out completely. Having witnessed the whole battle from having created fire, Konton states how good a show it was and smiles in satisfaction, now aware that the Half-Demon Princesses do have a weakness: The New Moon.

Trivia

 * This episode incorporates the arc with Nikosen, which only occurs in the manga from chapters 412-415 and was not adapted in InuYasha The Final Act.
 * It is revealed that quarter-demons like Moroha do not lose their powers like half-demons.
 * This is perhaps one of the first times that the main characters have donned their poison-shielding filter masks (only two masks are what they each have, however).
 * It explains why Towa never went though a demon power cycle in the Modern World.
 * It is also revealed why Setsuna doesn't lose her powers during the New Moon.
 * Its title is similar to "The Mystery of the New Moon and the Black-Haired Inuyasha" and shares similarities with it:
 * Both episodes feature the half dog-demon protagonist temporarily losing all of their abilities during the night of a new moon.
 * Their hair color also changes from silver to black.
 * Lack of knife-sharp dog fangs, claws and superhuman senses.
 * Inability to utilize their signature demon swords.
 * They regain their demon abilities at the last minute and save the day.

Episodio 12 (Hanyo no Yashahime)