Origin
Japan
Ein is a Smiling Mask mask under the control of Kuzuma Aohara. There wasn't much of her emotions displayed in both the manga and the anime, as she is often seen wearing her mask and is immobile unless commanded by her master. She, however, was seen exposing a personality trait of a child by sneezing carelessly in front of her master, Yuri, and her company. Her playfulness and innocence were also witnessed by her joy of rain and habit of sitting in accident prone railings of the rooftop. She wields katanas and appears to be proficient in using it. She was able to fight evenly against Mayuko Nise during their fight, along with cutting any surrounding objects in half.
High-Rise Invasion
High-school girl Yuri suddenly finds herself on the rooftop of a high-rise building. She's trapped in a bizarre world surrounded by skyscrapers, where a masked man cracks open a man's head with an axe before her eyes. She escapes from the masked man and tries to reach her beloved brother, who is also trapped in the bizarre world she's found herself in. Yuri proceeds to cross many high-rise buildings and take down every masked man along the way to find her brother and go home in peace. This marks the beginning of her adventure, which will span the wholeness of the realm they're in...and will reveal its truths.
