Yuusha no Kuzu

In contemporary Tokyo, Mafia bosses are now "Demon Kings," and "The Brave" are now legally authorized to hunt them. "Angel of Death" Yashiro, a freelance Brave, is roped into going up against a Demon King in Shibuya, by Aki Jogamine, a high school girl who is an apprentice Brave. But behind it all is an evil conspiracy that has permeated the entire city!

(Source: Mantra)