Ungaikyou - Sui

Ungaikyou (literally: "the mirror beyond the clouds") is a youkai made from the failure attempt of Amaterasu’s mirror called Mafutsu no Kagami (an alternate spelling of Yata no Kagami). Her duty is to protect and maintain order in the Infinite Corridor. She has a complex with being made from a "failure" and dislikes the Ayakashibito world. In an effort to

Spoiler

make the Infinite Corridor her own world, she pulled two wandering spirits from going to the netherworld…

Her name originally was only Ungaikyou, however after the creation of her little sister she added Sui after her name.