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.
mutsutake