Katana Eiyu
ErzaKurosaki
刀英雄 (Katana Eiyu): Sword Heroes
A light novel
In the city of Tokyo all the way to Kyoto, two ordinary people become known as "heroes" when they save the mayor. However, their faces were never broadcasted and their names were never released. They made the mayor promise not to tell anyone their identity.
Twins, Yuhei and Ayame work to help people of all kinds. Things go smoothly...until they meet clients with unexpected requests.
There are some references to Durarara~
(Original Story Started: June 2015) Was originally called Kurai Eiyu (Dark Heroes)