Yahirono Himorogi

About
The Yahirono Himorogi is an important artifact guarded by the fairies at Yoyogi Park. Several people enter the park searching for the stone to use it's power for their own goals. Sakahagi stole the stone and inflicted the fairies with a curse that robbed them of their senses. Chiaki entered the park and fought with Sakahagi before the fairies were cursed. She was defeated and maimed by Sakahagi (she lost an arm), yet managed to survive and limp away to safety.

Yuko also entered the park to find the stone, but soon gave up after sensing that she stood no chance of defeating the current possessor. She soon encounters Hito-Shura and tells him her purpose for wanting the stone; to force Aradia to give her a Reason (not realizing that she is the one whose suppose to conceptualize a Reason, or that Aradia is not even a 'real' deity). She then asks Hito-Shura to retrieve the stone in exchange for the Magatsuhi contained within it.

After managing to get through the pixies' traps, Hito-Shura meets Sakahagi at Cyber's construction site. Sakahagi tells him that he already used up all the Magatsuhi in the Yahirono Himoragi and that he will be the one using demons for now on--not the other way around. Sakahagi summons a Girimehkala to fight Hito-Shura, but the protagonist defeats both of them. After getting the stone he is thanked by Oberon and Titania for lifting the spell affecting the fairy clan. They allow him safe passage with the Yahirono Himorogi and bid him adieu.

After leaving the area Hito-Shura returns to Yuko and gives her the stone. Aradia possesses Yuko she asks him two important questions that will affect his destiny. After answering her Aradia tells the Hito-Shura that a Reason will soon be established in Ikebukuro and leaves.

Later, as the last Reason is being established, Yuko is used as a sacrifice to summon Hikawa's demonic sponsor, Ahriman. Before she fades away, Yuko gives the Yahirono Himorogi to Hito-Shura and tells him that his will is stronger than her's and that he should create his own world by using the stone to build a path to Kagutsuchi.

Hito-Shura heads to the Amala Temple and places the stone on an alter in the central pyramid. The stone activates and sends a beam of Magatsuhi to Kagutsuchi, who lowers his tower on top of the Obelisk, driving it into the ground.

History

 * Yahiro is a word that means 'enormously huge'.
 * A Himorogi is the most basic form of a Shinto shrine. In Shintoism, everything has a soul in nature and objects that hold very pure spirits are 'Himorogis', which are usually covered with special paper. Basically, a 'Yahiro-no-Himorogi' is an oxymoron, since it means a small basic object of gigantic size.