Otoha transforms into the armor-clad, katana-wielding Karas.
Karas takes place in Tokyo, a city populated by both humans and ghostly beings. They exist in two dimensions; seen and unseen - spirits, apparitions and demons. Karas is the city\'s guardian, and Tokyo is thrown into disarray as a former Karas named Eko attempts to seize power and bring order to the streets through force. An entity named Yurine, who represents the will of the people, stands in Eko\'s way with her newly risen Karas. Now two Karas emerge to destroy either all of the demons or destroy all humanity. Which Karas will prevail?