Star Instructor Master Bae is a Manga in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.starinstructormasterbaek.com fastest updating comic site. The Summary is

Once the finest instructor in the Blood Cult, Suryong Baek is killed, only to to wake up in the body of someone who teaches martial arts at a small rural academy. His new body may be weak, but he knows how to fix it, and it’s not the first time that he’s found himself in a body that can’t access its inner power. Curing his body requires money, however, and Suryong decides that becoming the greatest instructor at a top academy is the best way to do it. Since he’ll be up against tough competition, Suryong will have to use everything he’s got to become a teaching superstar. (Source: Webtoon Entertainment)