The cover and the description are most likely from the novel, I'm guessing the publisher hired a random artist for the cover and it was drawn with only a summary of the story, that is why the kid on it have nothing to do with the actual MC, not the translator fault, the bad cover was the most common.
The other covers are easy to find: https://www.google.com/search?q=%EC%98%A5%ED%83%91%EB%B0%A9+%EC%86%8C%EB%93%9C%EB%A7%88%EC%8A%A4%ED%84%B0&newwindow=1&rls=com.microsoft:it:%7Breferrer:source%3F%7D&sxsrf=ALeKk03zCP3d2YCZRHE2sUcFHSgIb_pIyQ:1598259955063&source=lnms&tbm=isch&sa=X&ved=2ahUKEwia2oSnvrPrAhUvMewKHUXPDRkQ_AUoAXoECAwQAw&biw=1355&bih=927