kusakabe_(kusakabeworks)
Artist.
Japanese name: 草壁 (Kusakabe or kskb)
Circle & site name: KusakabeWorks or kskbwrks
Old site & circle names: 宵月画房 (Studio Nox Selene), "duskfalls.org" or 夜営画室 (Nocturnal Atelier or Night Atelier)
The other circle: HEXIVISION (CPU's circle)