Justice Mask is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

A villainous space-time traveler randomly took over the body of a noble who was a role model of justice and obtained a system disguised as a villain's training manual! How was he supposed to choose between good and evil? To carry out justice or to play evil? Or simply both!