Looking at the artist "Un_Do" 's artwork, it seems that someone has merged his/her account with "ze_(sawakihein)" (http://www.pixiv.net/member.php?id=14168)'s work. The pieces are clearly by two very different artists. I can't fix it because the tag "Ze_(artist)" is no longer available for tagging.
The two has different pixiv accoutns as well. Unless I'm mistaken, and Un_do is actually the much older artwork for Ze. It doesn't seem like it, however.
Updated by user 11314