|Shadow Hearts: Covenant|
One of the three weapons used by Susano-o.
One of the Three Treasures, this royal mirror is imbued with the power of Japan's nature gods and hold the wild spirit of Raiden.
The only offensive ability it has is sending up beams of energy dealing moderate but not very significant damage to all party members. Occasionally, it can increase the special attack power of Susano-O and the other weapons.
The Yata no Kagami, is one of the legendary three Imperial Regalia of Japan. Representing the virtues of honesty and wisdom, it is presented to the new Emperor during their coronation, and said to be stored in the Ise Grand Shrine when not in use. It's name means "Eight-sided mirror".
In Japanese mythology, goddess of the sun Amaterasu, during a fued with her brother, the god of storms, Susan-O, she hid in a cave, depriving the world of the sun, and plunging it into darkness.
In a bid to rouse her from the cave, the other gods hung a mirror, from a nearby tree, garlanded it with necklace of magatama gems and made a ruckus, as though in celebration, claiming to have found a replacement light.
Curious, Amaterasu peered from the cave, and caught sight of her dazzling reflection, and moved out towards the mirror. The other gods sealed off the cave entrance, so she wouldn't be able to retreat back to it, and pleaded with her to carry on her duties, which she accepted.
The actual historical existance of the mirror is unconfirmed - there exists no contemporary pictures or illustrations, and only vague written accounts. Only high-ranking Shinto priests and the Emperor may see the treasure, and only then during the coronation.
In a time before the widespread use of mirrors, when they were only available to the wealthy, they came to represent truth and clarity - as they could only reflect reality, without the filter of preconception.