Oboro

Assembled mercenaries called the Oboro Forbearance Army, conspire with the evil spirits of rivers and mountains and the multinational conglomerate body. She's a female ninja supporting the nomads. Once the head of the school of Koka, she has greatly contributed to the expansion of influence and power within the nomads in Japan. On one occasion she is killed by Asagi, but from borrowing the evil spirits of rivers and mountains bodies, she's able to revive herself and dictate a dark arena known as the Chaos Arena. Burning with revenge, Oboro locates the whereabouts of Asagi's boyfriend, Kyousuke Sawaki, and ensnares and abducts him.

Ninja Arts: Hypnotism Carved Seal
Hypnotizing people, by manipulating a person's thoughts, she can make them fall into a deep sleep. Before that powerful ninja art is applied, it is said that a ritual must be carried out first. (Source: Dark Translations)