Tokyo Enma

In the year 20XX, the eruption of Mount Fuji caused a rapid deterioration in public safety in Japan, turning Tokyo into a crime-ridden city with an annual crime rate of 1.36 million. Chitose (15 years old), who transfers from Hokkaido to a high school in Tokyo, meets her classmate Ema (15 years old), whose hobby is watching adult videos. The girls head out into the dangerous streets after school. However, there are rumors that in this crime-ridden city of Tokyo there is a god called "Enma" who "eliminates" bad guys...

(Source: Kodansha, translated)