mutsutake
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.