Artist.

Japanese name: 深緑 or 深淵 (Shin'en) (Reading is "given by the artist":[http://www.pixiv.net/member_illust.php?mode=medium&illust_id=17197498])
Circle name: 玉露カンパニー (Gyokuro Company)
Defunct twitter username: sinen73
shin'en (gyokuro company)