Zanseiken

 is a sword wielded by the dog-hanyō Towa Higurashi. She acquires the sword in the Second Act of Hanyō no Yashahime. It is one of the two swords given by the god of stars,. The other is Kirinmaru's Bakuseiken.

History
After Towa plays the Star-Slicer Flute, it turns into the Zanseiken sword and fight against the Demon Spirit Beast of Mount Musubi. As she dodged from the green demon spirit's attack she was surprised that Kyūyōkon can absorb. Finally, she uses her recently developed Twin Azure Dragon Wave to destroy it. Some nights later, she uses it against some minor rock demons attacking her.

Physical description
The Zanseiken has a gold guard in a style similar to that of Kirinmaru's armor with a deep blue jewel embedded in it.

Powers & Abilities

 * Enhanced Slashing: As it is empowered by Towa's demonic energy, its ability to slice through solid objects is more effective.
 * Demonic Energy Absorption & Empowerment: Having the Kyūyōkon Root as part its formation, the Zanseiken can absorb large quantities of demon energy and becomes considerably stronger every second.
 * A stronger and more effective technique used by Towa, from the tip of her energy blade, she can unleash a powerful demonic energy wave in the form of a colossal blue-white twin head dragon, Kirinmaru was the one whom gave it the name. When she fought Kirinmaru for the third time, the dragons turned green.

Trivia

 * The Zanseiken was teased at the end of the first season finale.
 * The blue stone looks reminiscent of the Blue Rainbow Pearl.
 * A special flute known as Hoshikiri no Fue works in conjunction with this sword. When played, the flute transforms into the sword.
 * The Zanseiken is the second yōkai sword shown to transform, the first being Tessaiga.
 * In "Zero's Wish" it was not used when Towa turned into a full demon, but was replaced by her former energy blade from the broken Kikujūmonji replica.