I found these pics from the sites Gelbooru (originally) & chan.sankakucomplex that posted by these uploaders, but I'm not sure who drew them. They weren't seen, or originally drawn from somewhere in DeviantArt, Facebook, Twitter, Pixiv, etc. I even tried to figure out who drew them by using Saucenao, Google Images, but nothing. :? They all pointed to Gelbooru and that's it. So, I felt of posting them here to show everybody if anyone would recognize the drawing style somehow and would help me out with it. I actually like the pics of Maonyan (a.k.a. Cat demon girl Ring Announcer) from Shinmai Maou no Testament. :3
229azarashi: https://gelbooru.com/index.php?page=account&s=profile&id=257066 and tanukichi: https://gelbooru.com/index.php?page=account&s=profile&id=277434