minakami_hiroki
Illustrator, Character Designer, Doujin Artist.
Japanese name: 水上広樹, ぴろき (Piroki - Pixiv name)
Circle name: EXtage
See also
* Wikipedia article (JPN): http://ja.wikipedia.org/wiki/水上広樹
* Pixiv account: http://www.pixiv.net/member.php?id=543279