Birthday: November 4
Blood Type: B
Height: 147cm
Weight: 37kg
Three sizes: 65/54/74
Child: Miroku
Star sign: Scorpio

A middle school student of questionable origin who was pulled from the sea by a passing ferry. She is quite attached to Mai, though her purpose for going to Fuuka Academy is to search for her brother.

Her Element is a large jet-black claymore called Miroku, which responds to her calling whenever she is not near it. Miroku possesses several special powers including the ability to cut through almost any object, such as cruise ships without needing to be physically swung and the ability to summon energy blasts. When it uses these powers, glowing red eye-shaped markings appear on the blade. It is initially assumed that the sword itself is her Child, but her Child is later revealed to be a monstrous ogre-like creature which wields a gigantic spiked club, this also bears the name Miroku. This Child is called the protector of the Obsidian Lord and apparently seems to be under his control rather than Mikoto's (this is shown when Miroku made a vain attempt to stop Kagutsuchi's attack from destroying the Obsidian Lord).

Mikoto during the first few episodes behaves as though she was raised by cats (In My-Otome she is referred as the "Cat Goddess").