Blade of Retribution is a Manga/Manhwa/Manhua in english language, manga 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

On the day that Kendo Champion Shiho decided to help out his single mother run a Gukbap restaurant, he received news that his sister, Shiyeon, committed suicide. During the funeral, Shiho realizes that something was wrong. It wasn’t a suicide, she was murdered. In order to learn the truth and get revenge for his sister’s death, Shiho lifts up his sword once more to begin a war of his own.