So im looking for this manga or manhwa cant remember if it was korean or japanese but the stories takes place ib 21st century and the main protagonist doesnt fight but suddenly can and his skills will het triggered after a said word and he becomes very scary and than he suddenly enters a sort of system were bad behaving students can fight and thats the only place they can fight if fought outside of the system something happens and he won the first match against a very big person and surprised everyone

Hope you people can help me thank you very much i have may said it very confusing

Greatest outcast sounds really similar.