MANGNYANGTANGGEON: DOKKAEBI GAMTU

Mu-Won became a thief, following in his late father's footsteps. One night, while being pursued by the forces of the empire, he met a person whose identity he did not know. In a crisis situation, the suspect harassed him with ill-natured intentions and offered him a hat which could make his body transparent, and the only condition was that Mu-Won give him his body.

(Source: Lezhin, translated)