Artist.

Pen name: 神仙愚美 (Shinsen Gumi)
Nickname: N.G. (presumably taken from the N and G in his pen name)
Other names: 悠々 (yuyu) or ヨハン (yohan)

See also

• Pixiv account: http://www.pixiv.net/member.php?id=4872213
• Tinami account: http://www.tinami.com/creator/profile/33944