Artist.
Japanese name: 睦茸 (ムツタケ, Mutsutake)
Old name: 無月 (Mugetsuki)
Circle & site name: 怨床 (pronounced as Onshou, spelled as ON-SHOW) (Circle partner: Ishibashi Shingo)
This artist seems to be Mutsutake's Cookie_(Touhou)-themed account.
https://www.pixiv.net/users/68447
https://www.pixiv.net/users/14082741
https://www.pixiv.net/stacc/noconoco114
https://www.pixiv.net/stacc/tirumu1
https://twitter.com/62take
https://twitter.com/noconoco114
https://twitter.com/intent/user?user_id=109794212
https://twitter.com/intent/user?user_id=3133866583
https://seiga.nicovideo.jp/user/illust/679139
https://www.nicovideo.jp/user/679139
https://sketch.pixiv.net/@tirumu1
https://ask.fm/take826
http://blog.livedoor.jp/mutsutake/
http://onshow.sakura.ne.jp
http://www.amazon.co.jp/睦茸/e/B00IJ8P7TY/
https://pawoo.net/@noconoco114
https://pawoo.net/web/accounts/264342
http://twitpic.com/photos/62take