Yuusha no Kuzu

At the mid of 21st century, Tokyo’s underworld is controlled by demon lord. Criminal bosses are wandering freely and getting powers by doing surgery. Only heroes and bounty hunters fight against them. They use a special type of drug E3 to get powers. In this world survival is more important than justice. Yashiro, a lone hero who is known as the reaper, found a girl named Jougamine who insisted on becoming his students.