During my time looking around for Tera M art I may have an artist for this and the others.

A few pics on Google image search list a Yewon Kim but I'm still not entirely sure as I know nothing of Korean artists. There is a Yewon Lim here on Danbooru but I have no idea if they may be the same or not.

The names of all but one of Tera's official artists has always been a complete mystery to me. The only one I know of is Tera Japan's artist Byulzzimon.