Earth Caster is a co-living, co-operative using the technique of earth cast in a fully automated way to turn polluted brownfield soil into discrete earth-casted parts consisting a housing project. Through on-site casting, we rationalise linear toolpaths of a numerically controlled excavator to get a series of pits. We then pour in mud-concrete made from brownfield soil and cement to get the parts for assembly. Our platform seeks collaboration with the city council to get a lease on a cheap brownfield site so as to increase housing affordability towards young office workers. After the graph of general building trends is designed in response to the condition of a specific brownfield site, occupants would participate in the design process and a pix2pix image translator would convert the ownership diagram to a building volume. Lines representing toolpaths would be computationally generated and clustered afterwards. Parts are easily assembled by crane through feedback mechanisms based on photogrammetry and computational connection design. In addition, only lifting nodes and very simple prefabrications like bathroom or staircases are buried to keep our process simple and efficient. We hope that our occupants lead lifestyles of modern cave men, engaging in abundant co-living while appreciating the building in perspective of poetic brutality and imprecise grace.