Kensei Salaryman Musou: Osananajimi ga Tokidoki Jinrui wo Sukuu Tetsudai wo Tanondekuru

In Eastern Japan, there exists a samurai who fights against humanity's enemy, the phantom beasts, with extraordinary abilities. The salaryman Shinnosuke, who cares deeply for his little sister, is attacked by a phantom beast and unleashes his hidden power! In the heat of the moment, he even destroys a building, but is protected by his childhood friend Satsuki, who has become quite beautiful.

Furthermore, Shinnosuke realizes that the building he destroyed is a troublesome property related to his work. He comes up with a plan: if he can utilize this power, he can take care of his usual work problems! Using his abilities for personal gain in secret, he begins to assist Satsuki's samurai unit while hiding his true identity... but what will happen next?

(Source: Kakuyomu, translated)