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.