Fight Class 3 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 world in which Korea is the global capital of combat sports. At Nam-Il High School where the best and most talented students of martial arts reside, Jiu Ji-Tae suddenly finds himself thrust into their midst despite being a total weakling.
By neutralizing his physical shortcomings through jiu-jitsu, can he rise to the top of the fight classes?