Tale of the Sword Saint Beginning with Zero Attack Power is a Manga/Manhwa/Manhua in (English/Raw) 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

While Eugene was blessed with an extraordinary talent for defensive magic, on the other hand, he had no aptitude for offensive magic. Ridiculed as incompetent by those around him, he enrolled in a magic academy to run away. However, there, his “useless” defensive magic was highly valued, and astonishingly, he was appointed as the caretaker of the beautiful Demon Queen, Erynyes, who once ruled the world—!?