Google Image Search pointed me to a Korean light novel and image hosting website (I assume) here, with a link to a blog that has a lot of art of the same style here. Notably, artist #12053 's blog is also on naver.com, so I'd guess that "grangdash" is the original artist? However, looking through all of the blog, I didn't find this image, and I'm completely unfamiliar with Korean so properly navigating through more of Seed Novel and the blog is hard.